CAPE VERDE: “It now presents a melancholy, but very picturesque appearance....We visited a collection of buildings, of which an ancient church formed the principal part,” Charles Darwin wrote of his visit to Cidade Velha, former capital of what was then a Portuguese trading colony. Researchers have found the remains of a 500-year-old church that may have been the one he visited. It is the oldest building in the islands, and the oldest known European church in the tropics. As many as 1,000 people, many of them African slaves, are likely buried beneath. —Samir S. Patel