In more recent history, primarily since the country discovered oil in the 1930s, many historic buildings were torn down and new, modern buildings were constructed, again primarily in Kuwait City. These modern buildings are no different from other modern buildings, using materials and machines created by the Industrial Revolution, including concrete, steel, and cranes. There are numerous modern buildings in Kuwait City, the city's water towers being the most iconic of these architectural monuments. Kuwait Towers is also an impressive landmark.