The Basilica of Saint Louis, King of Saint Louis, commonly known as the Old Cathedral, is the oldest cathedral west of the Mississippi River. A succession of log churches stood on the spot known as the Cathedral Block from about 1770 until construction began on the Greek Revival-style structure in 1831. The landmark escaped the inferno of the Fire of 1849, the land clearance of 82 acres for the Jefferson National Expansion Memorial and a brush with the Interstate Highway System in the Downtown neighborhood.