The Andaman islands Located in the Bay of Bengal, this group of 572 islands of which less than 50 are populated, lies 193 km away from Cape Negrais in Myanmar, 1255 km from Calcutta, and 1190 km from madras. The two important groups of islets are Ritchie's Archipelago and Labyrinth Islands. The Andaman and Nicobar Islands is formed by a submarine mountain range, which separates the Bay of Bengal from the Andaman Sea. The islands attain maximum altitude of 730 m. Little is known historically about Andaman and Nicobar. It is believed that Marco Polo was among the first from the West to set foot on one of the islands. Kanhoji Angre, a Maratha admiral had his base on the island in the early 18th century. From there, he attacked passing Portuguese, Dutch and English merchant vessels. Kanhoji Angre was never defeated. He died in 1729. The British established their first colony in the Andaman and Nicobar Islands in 1789, which was abandoned in 1796. The British finally annexed the islands in the 19th century adding them to their empire. They turned it into a penal colony for Indian freedom fighters. The construction of the Cellular Jail was completed in 1908. Hundreds of anti-British Indians were tortured to death or simply executed here. With the Second World War, Japanese troops occupied the islands. When India achieved independence in 1947, the Andaman and Nicobar Islands were incorporated into the Indian Union.