The Virgin Islands are group of about 100 small islands located at the East of Puerto Rico. They were discovered by Columbus in 1493. Six out of the nine main islands has been British since 1666. The remaining three (St. Croix, St. Thomas, and St. John), as well as about 50 of the smaller islands, were eventually acquired by Denmark, which named them the Danish West Indies. In 1917, these islands were purchased by the U.S. from Denmark. Congress granted U.S. citizenship to Virgin Islanders in 1927.