The world's wealthiest countries weren't always so affluent. Believe it or not, some mega-rich nations featured in this list used to be seriously poor and had to overcome major economic obstacles to get to where they are today.

Read on as we chart the rise of 10 countries that turned their fortunes around to become the most prosperous nations on the planet.

All GDP figures from World Population Review unless otherwise noted.

All dollar values in US dollars.

Rolling in money, Luxembourg has the third-highest GDP per capita in the world at around $125,897 (£98.9k). The principality's perfectly diversified economy is based on banking, steel, and advanced manufacturing. 

It's hard to imagine Luxembourg as a poor country, but that's exactly what the landlocked European nation was during the early 19th century. Around 80% of the population, approximately 180,000 people, were employed in agriculture and life was far from easy.

Trapped in grinding poverty, many families could barely afford to survive. Things got so bad that about a third of the population left to seek a better life elsewhere, heading mostly to the USA.

The discovery of significant reserves of iron ore in the mid-19th century changed Luxembourg's fortunes almost overnight. Mines and factories sprung up, and the country's lucrative steel industry was born. By the end of the 19th century, Luxembourg had become one of Europe's leading steel producers.

The steel industry thrived, and jobs abounded throughout the 20th century, except during the two world wars. Luxembourg developed banking and advanced manufacturing industries in the 1960s, and since then the economy has been in excellent shape, enriching the compact country massively.

Today, Switzerland is synonymous with wealth and economic success. The country boasts some of the highest standards of living in Europe and its GDP per capita of around $93,636 (£73.6k) plants it firmly in the world's top 10.

However, rewind 150 years and Switzerland was a poor nation. The landlocked country's mountainous terrain presented a major obstacle to development, industry was relatively primitive, and a large proportion of the population – particularly rural dwellers – had emigrated to escape a life of poverty.

In the late 19th century, a period of industrialisation nurtured by favourable economic policies began to transform the economy. At the same time, the country's banking and tourism industries started to blossom. Switzerland was fast becoming one of Europe's richest nations.

The momentum continued into the 20th century. Switzerland's famous policy of neutrality allowed the country to escape the ravages of the two world wars and profit from arms exports and bank loans.

The Swiss economy transitioned from an industrial to a service economy in the 1950s. Today, around 74% of the country's GDP is generated by the services sector, while 25% comes from industry (the remaining 1% comes from agriculture).

Although growth slowed down in the 1970s, Switzerland remains enviably wealthy with relatively low levels of government debt.

Norway's GDP per capita of around $106,622 (£83.9k) is one of the highest in the world. The nation has an oil fund worth approximately $250,000 (£197k) per Norwegian citizen and, in recent years, has consistently taken the top spot for standard of living in the UN's Human Development report.

However, hardship prevailed in Norway during the 19th century. The bulk of the population worked in the agriculture and fishing industries, and wages were appallingly low. By the early 20th century, around 800,000 Norwegians had left to try their luck in the USA. 

The country's financial situation improved in the early 20th century when the Norwegian government began to develop a hydroelectric power industry, which provided jobs and boosted GDP.

Norway entered recession in the 1930s along with the rest of the world and the economy was crippled by World War II. Following the war, Norway recovered rapidly thanks to funding from the US and had returned to prosperity by the 1960s.

In 1969, substantial oil and reserves were discovered in Norwegian territorial waters. Production began in 1971, and as the price of oil rose during the 1970s, so did Norway's GDP. The proceeds from the oil industry have allowed the country to develop a welfare state that is envied the world over.

Brunei's GDP per capita today is around $37,152 (£29.2k). But prior to the discovery of enormous oil reserves in 1929, Brunei was a struggling British protectorate with high levels of poverty. It chiefly relied on the export of rubber and sago (palm tree starch) to power its economy.

This photo of the former royal palace reflects just how poor Brunei really was.

Despite the Great Depression and World War II, which stalled the growth of the oil industry, the sultanate became steadily richer during the 1930s and 1940s from exports of "black gold", reaping bumper royalties.

The 28th Sultan, Omar Ali Saifuddien III (pictured), implemented a series of National Development Plans during the 1950s and 1960s. The reforms updated infrastructure, created an advanced education system, and massively improved public health. 

Natural gas reserves were discovered in the 1960s, and by the early 1970s the economy was booming and the standard of living in Brunei was virtually on a par with Europe and North America. Additional reserves of oil and gas were found offshore in the 1970s, bolstering the economy further. 

Since Brunei gained independence from the UK in 1984, oil and gas prices have dictated economic growth, which has fluctuated from highs of around 4.5% to lows of -2.5%. But the nation remains wealthy and the royal palace (pictured) is rather grander these days.

At the outbreak of the Korean War in 1950, Korea was on its knees following decades of Japanese occupation. The industrialised North was actually wealthier than the South, which was focused more on crops and farmland. 

The war ended in 1953 and South Korea remained in the economic doldrums until a coup in 1961 ushered in a military junta led by General Park Chung-hee. While the regime has been criticised for curtailing civil liberties, it effectively modernised the South Korean economy.

The country's first Five Year Plan was implemented in 1962 and rapid industrialisation followed. The nation's swift and remarkable progress was dubbed "the Miracle on the Han River" after the phrase "the Miracle on the Rhine" was coined to describe Germany's remarkable post-war economic recovery.

South Korea's famous family-run chaebol conglomerates such as Samsung and LG were guaranteed huge loans from the banking sector and special treatment as part of the first Five Year Plan. They and the nation's economy enjoyed jaw-dropping growth throughout the 1960s.

The country's steel and electronics industries flourished in the 1970s and growth topped 7.8%. By the time military rule ended in 1993, South Korea had become a developed nation.

Nowadays, the country's GDP per capita is in the region of $32,305 (£25.4k), dwarfing North Korea's $590 (£464). It's also higher than countries including Portugal, Malaysia, Brazil, and Spain...

Spain was originally a poor agricultural country that was devastated by civil war in the 1930s. This resulted in a repressive dictatorship that stifled the economy for decades, and the financial situation remained dire throughout the 1940s and 1950s.

The fascist government of General Francisco Franco focused on economic self-sufficiency during these decades, closing Spain off from the outside world and curtailing imports. This policy led to negative growth, a devalued currency, and severe shortages of essential goods.

As Western Europe became richer, Spain seemed to be going backwards. In 1959, Franco changed tactics and replaced the old guard in his government with younger, economically liberal ministers, initiating the first of Spain's development plans to kick-start the economy.

During the 1960s, Spain industrialised heavily and opened up to the outside world. Many factories were built around the country and tourism boomed. GDP per capita, which was only $7,359 (£5.2k) in 1960, had more than doubled by the time fascist rule ended in 1975.

Since 1975, Spain has transitioned to an affluent modern democracy. The country joined the EU in 1986 and years of growth and rising living standards followed. Today, its GDP per capita stands at around $29,771 (£23.4k). 

The economy took a battering during the Great Spanish Recession of 2008 to 2013 but is now on the road to recovery. It's also seen a massive boom in tourism revenue since COVID-19 restrictions were relaxed.

When Singapore gained independence from Malaysia in 1965, the tiny city state was plagued by poverty and high unemployment. A third of the population lived in squalid slums, up to half the new nation's residents were illiterate, and GDP per capita was stuck at just $516 (£362).

With no natural resources, Singapore's economic prospects were looking very bleak indeed. The country's saviour came in the form of its first prime minister, Lee Kuan Yew, who set about transforming Singapore into a highly developed metropolis. 

The visionary and sometimes authoritarian prime minister overhauled the education system and made English the common language, creating a highly skilled multilingual workforce. At the same time, Lee clamped down on corruption, slashed taxes, and – controversially – banned trade unions in an attempt to attract foreign investment. 

Lee's policies had the desired effect and foreign money poured in, stimulating double-digit growth. The government spent its new-found wealth on improving Singapore's infrastructure, housing, and other amenities. By the 1970s, the standard of living in the up-and-coming city state had markedly improved.

When Lee stepped down in 1990, Singapore had become the glittering city-state he'd envisaged all those years ago.

Today, the economy is ranked among the most open and business-friendly in the world and living standards are high. Meanwhile, its GDP per capita is one of the highest in the world at around $78,144 (£61.4k), larger than the UK, the US, and Germany.

Saudi Arabia was among the poorest countries in the world when it was founded in 1932. The country depended on the revenue generated from worshippers undertaking the Hajj pilgrimage to Mecca, as well as income from agriculture, which was modest and unpredictable.

The Gulf state was woefully undeveloped, lacking everything from housing and hospitals to proper roads and reliable electricity. The majority of the population was unable to read or write and lived very simple lives.

All that changed in the late 1930s. The discovery of colossal oil reserves in 1938 was an epic reversal of fortune for the needy country. By the late 1940s, Saudi oil wells were pumping out barrel upon barrel of the commodity, but the country really cashed in from the 1970s onwards.

The 1973 oil crisis pushed up prices and massively enriched the Saudi economy. Prices dropped during the mid-1980s and were low until the late 1990s. During this time, Saudi Arabia racked up substantial foreign debts, but its citizens maintained a high standard of living.

The government balanced the books when the oil price picked up in the late 1990s and stayed high until the late 2000s. When prices started to dip, Saudi Arabia began the process of diversifying its economy – but its oil reserves have proved staggeringly profitable as much of the world turns its back on Russia's supply.

Although Crown Prince Mohammed bin Salman's super-ambitious Saudi Vision 2030 plan aimed to reduce the country's dependence on oil, the nation made more than $200 billion (£157bn) from oil revenues last year. Its GDP per capita today is around $30,436 (£23.9k).

Like Saudi Arabia, Qatar was an impoverished country during the early part of the 20th century. The Gulf state, which became a British protectorate in 1916, was reliant on fishing and pearl diving (pictured), and most Qataris had to work long and hard to make a decent living.

Oil was discovered in 1940, but World War II put a halt to further exploration, and it wasn't until 1949 that Qatar began producing the black stuff in earnest. Flush with oil money, the Middle Eastern country modernised at breakneck speed during the 1950s and 1960s. 

When Qatar gained full independence from the UK in 1971, the country was reaping the rewards of more than two decades of oil extraction. Industry and infrastructure were much better developed, and the general standard of living had improved greatly.

The increase in the price of oil during the 1970s drove impressive growth, but the commodity's falling price from 1980 to 1997 stagnated the economy. When the oil price recovered in the late 1990s, Qatar experienced a sustained period of economic growth.

Since 1997, real GDP growth has peaked at an astonishing 30%. Qatar has put more of a focus on natural gas extraction and, like Saudi Arabia, is keen to diversify its economy. However, oil is still a huge money-maker for the nation.

Today, Qatar boasts one of the highest GDP per capita in the world at around $87,974 (£69.2k) – putting it way ahead of the likes of Canada, France and Australia.

Back in the early 1990s, Ireland was one of the poorest countries in Europe, with a GDP per capita of just $14,000 (£9.8k). Unemployment and inflation were high and economic growth had stalled. The general standard of living was low and much of the rural population struggled to get by.

The luck of the Irish worked its magic from the middle part of the decade to the late 2000s, and growth skyrocketed to 9.4% during the so-called "Celtic Tiger" period. Attracted by an increasingly educated workforce and favourable business rates, foreign businesses flocked to the Emerald Isle.

Unemployment plummeted from almost 16% in the early 1990s to just 3.9% in 2001, and the standard of living in Ireland rose to rival that of the richest countries in Europe. Irish consumer spending hit record levels, construction boomed, home ownership soared, and GDP per capita hit $61,000 (£45k) by 2007.

The party ended in 2008 when the Irish economy fell into recession. The fallout from the global financial crisis was aggravated by a severe housing bubble, and Ireland was forced to accept an EU and IMF bailout package. A period of austerity followed.

Since then, Ireland – which has the world's sixth-highest GDP per capita at $105,993 (£83.3k) – has made a spectacular comeback. It's been one of the fastest-growing economies in Europe in recent years, and an upsurge in foreign investment and increased consumer spending are working wonders on the nation's finances.

Now discover nine countries that used to be rich and why their fortunes faltered