This year approximately 14,000 vessels transited the Panama Canal’s series of locks connecting the Atlantic Ocean to the Pacific. Vital for international maritime trade, the canal allows ships to avoid the hazardous route around Cape Horn and shortens what would have been a 13,000-mile journey around the tip of South America into an eight-hour voyage through the 48-mile waterway that cuts through the Isthmus of Panama. 

This video by Business Insider shows how ships move through the canal:

In operation for more than 100 years, the Panama Canal may soon have a neighbor in Nicaragua, the potential site of one of three new mega-canal projects that include proposals for Thailand and Iran. While these projects could potentially ease congestion on shipping routes, reduce global carbon emissions and create new economic opportunities, the arguments against these schemes include concerns for the impact of invasive species and lack of funding for construction and infrastructure.

The smallest project, the 31-mile canal proposed to cut through Thailand’s Kra Isthmus, is estimated to cost $20 billion. The 870-mile canal through Iran, linking the Caspian Sea with the Persian Gulf, would traverse through mountains and require more than 50 locks but would only cost $7 billion to construct, according to an estimate in 2012 from the former Iranian Energy Minister Majid Namjoo. The future of both projects will be affected by the success of the 170-mile canal through Nicaragua, which has suffered from a stall in construction due to lack of funding and complex political relations between China and Central American governments.