What is true about the Guano Islands?

* They were previously claimed under the Guano Islands Act, which allowed the United States to claim unoccupied islands containing guano.

* Over 70 islands were claimed, mostly in the Pacific Ocean.

* The last U.S. guano island claim was made in 1972.

* These claims allowed the U.S. to expand its territory and resources.

* Today, most of these islands are uninhabited and are home to various wildlife species, including seabirds and marine mammals.