In operation for 110 years, the Panama Canal is one of the world's greatest feats of engineering. It's also a vital component in global trade: around $270 billion (£217bn) worth of cargo passes through each year, with the canal slashing travel time and enabling crucial and cost-saving 'just in time' fulfilment for manufacturers and retailers. 

However, the canal now faces several enormous challenges – not least President Trump's threat to seize control of it – throwing its future into doubt. What's more, neighbouring countries are already working on replacement solutions. 

Read on to discover the story of its construction, the big problems it faces and four huge foreign projects that could rival the Panama Canal.

All dollar amounts in US dollars.