Here's a quick comparison:

* Black Sea: 436,400 square kilometers (168,500 square miles)

* Red Sea: 438,000 square kilometers (169,100 square miles)

While the Red Sea is slightly larger in surface area, the Black Sea is deeper. The Black Sea has a maximum depth of 2,212 meters (7,257 feet), while the Red Sea's maximum depth is 2,211 meters (7,254 feet).