Travelers may disagree on which sites deserve to be considered modern wonders of the world, but the Panama Canal would surely make most short lists. The shipping channel—which took 33 years to complete and cost 25,000 workers their lives—is arguably the greatest engineering project ever. Today, a journey through the canal will take you from the port of Colón on the Atlantic to bustling Panama City on the Pacific. Along the way, you'll find Gatun Lake, once the largest manmade lake in the world, which has proved a boon for Central American species that thrive here, undisturbed by the ships passing by.