Mississippi River, Missouri, USA
Riverside environment, urban area
Founded by French settlers in the 1600s and named for King Louis IX, St. Louis has historically been a major hub of transportation along the Mississippi River, having spawned steamboat travel in the 1800s after its acquisition by the United States. It was one of the major stopping points of the Lewis and Clark Expedition exploring the West after the Louisiana Purchase, which is commemorated by its iconic landmark, the Gateway Arch.
Great World War III
In the Third World War, St. Louis was one of many cities to fall under siege by the Soviet Union during their invasion of the country, and was quickly occupied by the enemy along with the rest of Missouri. Unlike many major cities in the initial invasion, St. Louis was spared from major damage, but its civilian population was helpless to repel their captors. After the Europeans gave the Americans the momentum they needed to launch a counteroffensive, the Allies moved in to retake Missouri, now a major staging ground for both sides in the war.
Unfortunately, the Soviets retaliated with a desperate counterattack by invading the city and installing a Psychic Beacon in the remains of Busch Stadium, now partially destroyed by the Soviets. Every American soldier and civilian within the city limits became mind-controlled slaves, so the Americans responded by sending Special Agent Tanya and her team to destroy the beacon. Tanya and her team successfully fought their way past the Soviet patrols and destroyed the beacon, liberating the city's citizens.
The Americans took advantage of the enemy's weakness and launched an amphibious assault near the Gateway Arch, where they deployed the highly-lethal Prism Tanks, a mobile version of Albert Einstein's Prism Tower for the first time. However, the Soviets responded to this by sending their Desolators to eradicate a large number of civilian prisoners in an attempt to intimidate their foes. Unsurprisingly, this insane tactic did not sway the Americans, who were determined to take their city back.
The Americans reestablished control of an Allied installation damaged in an earlier attack by the Soviets and soon built up its forces. In a concentrated assault with Tanya's help, the Americans wiped out the Soviet forces in the area, saving St. Louis and further rolling back the desperate Soviets.