For hundreds of years, explorers and governments have dreamed of a waterway linking the Atlantic and Pacific. Proposed routes have ranged from Mexico to Colombia, but many have focused on Nicaragua.

A multi-billion dollar Chinese plan to plow a massive rival to the Panama Canal across the middle of Nicaragua was headed for approval by the leftist-controlled National Assembly Thursday, capping a lightning-fast approval process that has provoked deep skepticism among shipping experts and concern among environmentalists.