When it comes to vital infrastructure, defence, and other critical spending priorities, governments around the world have been known to dig deep – with public money clearly no object.

In fact, the expenditure for some megaprojects can be truly mind-blowing, with grand totals that comfortably stretch into hundreds of billions.

From post-disaster reconstruction efforts to high-speed rail links, read on to discover the astronomical projects that have been fully or partly funded by the state in 28 countries around the world.

All dollar values in US dollars unless otherwise stated.