Aircraft carriers are the pinnacle of modern naval achievement. The massive vessels serve as warships as well as nautical air bases that can deploy and recover airplanes. Large and expensive, only the wealthiest nations can afford to build and maintain aircraft carriers.

The majority of all the aircraft carriers in the world sail under the Stars and Stripes. There are 20 active aircraft carriers, 11 of which are American. Italy has two carriers, and Brazil, France, China, India, Russia, Thailand, and the UK have one each. Other countries have similar ships, like Japan’s “helicopter destroyers,” but there are only 20 vessels in the world that can launch fixed-wing aircraft from the ocean.

There have been more than 60 U.S. aircraft carriers assembled and commissioned over the years. Most of these ships were commissioned in the early 1940s, around the time the United States entered World War II.

Four were sunk by enemy action in World War II. Others have been sold for scrap, permanently docked for use as museums, or sunk intentionally — whether for weapons testing or to be used as an artificial reef in the ocean. The USS Wasp was sunk by Japanese torpedoes in the Coral Sea and just recently discovered.

It will likely be more difficult to decommission existing aircraft carriers, as they are all nuclear powered. The first nuclear-powered carrier, the USS Enterprise, was decommissioned in 2012, and the Navy is still struggling to figure out how to remove and dispose of its nuclear reactors.

These are the U.S. Navy’s 11 active aircraft carriers.