Water covers nearly three-quarters of the Earth's surface, and beneath the waves lie an array of precious treasures. Hoards of New World coins, spoils of war, and invaluable archaeological artefacts are just some of the underwater discoveries that have made a splash. And that's just the tip of the iceberg... 

Read on to discover more incredible treasure troves that have been found underwater, including a "significant" new discovery off the coast of Sardinia. All dollar amounts in US dollars with values adjusted for inflation.