Gateway Arch is a memorial arch and observation tower designed by Eero Saarinen in 1947. It located at St. Louis, Missouri as the Gateway to the West.

The height is 630 feet (192 m), and 630 feet wide at its base. It used stainless steel skin which covering two carbon steel walls. In the middle of the building, it used reinforced concrete as the construction from ground level to 300 feet (91 m), and from 300 feet to the peak, it used carbon steel and rebar(reinforcing bar, a common steel bar used in reinforced concrete and reinforced masonry structures).

The interior of the building is hollow and on the top of it, there is an observation deck. To achieve the top of the building, it provide an unique transport system called tram system.

Tags: Building, Carbon steel, Construction, design, Eero Saarinen, Gateway Arch, Interior, Rebar, Reinforced concrete, St. Louis, Stainless steel, Steel,