the island's lighthouse has been in operation since 1700; it is named for the opposite point on the mainland, "hoek van 't ij", or "corner of the ij". the first lighthouse was a square, stone building. in 1809, the island was equipped with a military post, which, in 1844, was expanded to a real fort, which, in 1883, became a part of the stelling van amsterdam. the lighthouse was replaced with a cast-iron construction in 1893, which is still standing.