AP Photo

The Bab el-Mandeb, the strait that separates the Red Sea from the Indian Ocean, has conjoined Africa and Asia for centuries. It likely was the first route taken by Homo sapiens on their journey out of Africa, and the traffic between the Horn and Arabia has continued apace to this day. Men, goods, and ideas have gone back and forth, giving the Arabian Sea a degree of integration and similarity that is obfuscated by the arbitrary taxonomy of modern geography: Africa vs. Asia; the Horn of Africa vs. Arabia vs. South Asia. Only some 3,300 kilometers (about 1,800 nautical miles) separate Mumbai from Djibouti, the extreme range of a series of seaports and islands that dot the Arabian Sea: Massawa, Djibouti, Aden, Berbera, Mogadishu, Socotra, Muscat, Hormuz, Gwadar, Karachi,...