Aja, Egypt

Living in this former slave trading post turned fishing village means confronting stark coastal erosion that has already wiped out most of the historic architecture. With 57,636 residents as of 2013, Grand-Popo sits along Benin's southwestern coast, spanning 289 square kilometers where the Mono River meets the Atlantic.

What began as the ancient kingdom of Hulagan evolved into a major 17th-century European trading post, with brick buildings concentrated in the Gbekon quarter near the central market and beach. By the late 1950s, aggressive coastal erosion had devastated the original town, destroying early Catholic and Protestant missions along with the area's first school. Today's Grand-Popo survives primarily on fishing, while also gaining recognition as a voodoo center and home to the Finnish-African cultural center Villa Karo.