Malta is the largest island of the Maltese archipelago. The whole country with its three main islands and numerous small ones is also called Malta, which sometimes causes confusion. For this reason the island is also called Valletta, after the capital city of the island. The island is 27 km long, 14 km wide, and has a surface of 246 km². It consists of limestone and is karstified, so there are numerous caves all over the island.