The interior of the Arch is hollow and contains a unique transport system leading to an observation deck at the top. The interior of the Arch also contains two emergency stairwells of 1076 steps each, in the event of a need to evacuate the Arch or if a problem develops with the tram system. By 1968 a unique tram system that combined an elevator cable lift system with gimbaled cars functionally similar to ferris wheel gondolas had been installed. Thirty-two small windows (16 per side) measuring 7 x 27 inches (178 mm x 686 mm), almost invisible from the ground, allow views across the Mississippi Riverand southern Illinois with its prominent Mississippian culture mounds to the east at Cahokia Mounds, and the City of Saint Louis and St. Louis County to the west beyond the city. On a clear day, one can see up to thirty miles (48 km).
The interior of the Arch is hollow and contains a unique transport system leading to an observation deck at the top. The interior of the Arch also contains two emergency stairwells of 1076 steps each, in the event of a need to evacuate the Arch or if a problem develops with the tram system. By 1968 a unique tram system that combined an elevator cable lift system with gimbaled cars functionally similar to ferris wheel gondolas had been installed. Thirty-two small windows (16 per side) measuring 7 x 27 inches (178 mm x 686 mm), almost invisible from the ground, allow views across the Mississippi Riverand southern Illinois with its prominent Mississippian culture mounds to the east at Cahokia Mounds, and the City of Saint Louis and St. Louis County to the west beyond the city. On a clear day, one can see up to thirty miles (48 km).