The arch was built primarily to commemorate significant historical events and achievements. The Roman triumphal arch, for example, was constructed to celebrate military victories and honor victorious generals or emperors. These arches were symbolic monuments representing triumphs granted by the Roman Senate, often decorated with reliefs depicting victories and inscriptions praising the triumphator.
Specifically, the Gateway Arch in St. Louis was built as a monument symbolizing the westward expansion of the United States, commemorating Thomas Jefferson, the Louisiana Purchase of 1803, and the subsequent opening of the western part of the country to settlers after the Lewis and Clark Expedition. It serves as a "Gateway to the West," representing exploration, bravery, and the nation's growth.
Thus, arches in general were built either as monuments of triumph and honor in ancient Rome or as symbolic memorials reflecting significant cultural and historical milestones in the modern era.
