The Louvre or the Louvre Museum is one of the world's largest museums and a historic monument in Paris. Nearly 35,000 objects from prehistory to the 21st century are exhibited over an area of 60,600 square metres (652,300 square feet). The Louvre is the world's most visited museum, receiving more than 9.7 million visitors in 2012. The museum is housed in the Louvre Palace, originally built as a fortress in the late 12th century under Philip II. Remnants of the fortress are visible in the basement of the museum. The building was extended many times to form the present Louvre Palace.