St. Kitts, the larger of the two islands, is roughly oval in shape except for a long, narrow peninsula to the southeast. The Narrows, a 2-mile- (3-km-) wide channel, separates the two islands. The circularly shaped Nevis is surrounded by coral reefs and the island is almost entirely a single mountain, Nevis Peak (3,232 ft [985 m]). Government is a Constitutional monarchy. When Christopher Columbus explored the islands in 1493, they were inhabited by the Carib people. Today, most of the inhabitants are the descendants of African slaves. The British settled on St. Kitts—formerly St. Christopher—in 1623, and on Nevis in 1628.