The origins of the first roller coaster are a blend of 18th-century Russian winter traditions and 19th-century French engineering. The earliest progenitors were the "Russian Mountains"—massive, wooden-supported ice slides built in the 1700s near Saint Petersburg, where riders would plummet down steep 70-foot drops in sleds. The first "modern" version with wheeled cars on a track was Les Montagnes Russes à Belleville, which opened in Paris in 1817. This featured cars that were actually locked to the track for safety. Shortly after, the Promenades Aériennes (Aerial Walk) also opened in Paris, featuring a heart-shaped layout. In the United States, the first commercial roller coaster was the Switchback Railway, designed by LaMarcus Adna Thompson and opened at Coney Island in 1884. While the French designs were the first to use wheels and tracks in a circuit, it was Thompson’s Coney Island creation that sparked the global "Golden Age" of amusement parks, leading to the development of the complex, high-speed thrill machines we recognize as roller coasters today.