The decade was opened with a very hostile political climate around the world. Napoleon was invading France's neighbours in efforts to build a French Empire, causing a chain of global-scaled conflicts known as the Napoleonic Wars. Here, France's Napoleonic empire saw its rise and fall through events such as Napoleon's attempts to conquer Russia, the War of 1812 (spillover to America), and the Battle of Waterloo (Napoleon's ultimate defeat). Imperialism began to encroach towards African and Asian territories through trade, as the United States saw mass-scaled migration that headed westward towards the American frontier (mostly through the opening of the Oregon Trail.)