Long Beach is the largest city in Southern California and is part of Los Angeles County, situated between Los Angeles to the North and Orange County to the South. Long Beach is the sixth largest city in all of California and the 36th largest in the country. It is estimated that 492,682 people call the city their home as of 2008. The Port of Long Beach is one of the largest shipping ports in the world, and is also home to the cities oil industry. The Port of Long Beach is the second busiest sea port on the world as of 2005. Long Beach is also home to the RMS Queen Mary; the ship was used as a commercial vessel and also a troop transportation vessel during WWII. The 1936 ocean liner is permanently docked in the harbor and is now used as a maritime museum and hotel. Another hot spot in Long Beach is the non-profit Aquarium of the Pacific, located in Downtown. The aquarium opened in 1998 to the public, and since then has hosted over 13 million visitors. The aquarium is host to nearly 12,500 animals making up 550 aquatic species, ranging from mammals such as sea otters to jellyfish. The aquarium has three permanent exhibits focusing on the different areas within the Pacific Ocean: the cold water of the Northern Pacific, Southern Californian and Baja and the reefs of the Tropical Pacific. Due to how close the city is to the Pacific Ocean, the temperature remains moderate throughout the years. Temperature readings are taken at the Long beach airport, located four miles inland from the ocean. Many freeways run through the city, helping to connect it to Los Angeles, Orange, and San Diego Counties. In addition to its freeway systems, Long Beach has several modes of public transportation; home of a Metro Blue Line light rail terminal, Amtrak bus transportation, and Greyhounds are ways for commuters to travel. Public transportation in the city is provided by Long Beach Transit.