When the Switchback Railway debuted at New York's Coney Island in 1884, it signaled the arrival of the amusement park. Correspondent Tracy Smith looks at the origin and evolution of an American institution.

Amusement park rides and sideshows, hot dogs, and mermaid parades: Coney Island, a tiny stretch of beachfront in Brooklyn, has left an indelible mark on the world's popular imagination for nearly 150 years.