Baku is the capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and of the Caucasus region. At the beginning of 2009, Baku's urban population was estimated at just over two million people. The city is the scientific, cultural and industrial center of Azerbaijan. Many sizeable Azerbaijani institutions have their headquarters there, including SOCAR, one of the world's top 100 companies. The first oil well was mechanically drilled in the Bibi-Heybat suburb of Baku in 1846, though a number of hand-dug wells predate it. Large-scale oil exploration started in 1872, when Russian imperial authorities auctioned the parcels of oil-rich land around Baku to private investors.