In 1804 President Jefferson sent explorers Lewis and Clark out to discover the new purchased Louisiana Territory. When they explores came to St. Louis they found more than 1,000 people mostly a mixture of French, Spanish, Native American, and African Americans living in St. Louis. The city was a hub for fur trading in America. St. Louis became the last stop for hunters to sell their furs before heading out west to explore. The booming fur trading market lasted in St. Louis until about 1840.
The first riverboat stopped in St. Louis in 1817 marking the beginning of St. Louis becoming a major trading city. Docks were built on the river as well as warehouses for all the goods being imported and exported from the city. Many people stopped in St. Louis before heading to California during the gold rush. This is the time in which St. Louis was dubbed The Gateway City. In 1849 there was a major fire in the city caused by a steamboat explosion. The fire did more than 6.1 million dollars in damage to the city. The parts of the city that were destroyed were rebuilt. Two of the most historic buildings that were not burned in the fire are the Old Courthouse and the Old Cathedral which are now apart of the Jefferson National Expansion Monument and are still open to the public.