Exactly 56 years ago this week, the awe-inspiring Gateway Arch was completed. The vision of architect Eero Saarinen, the Gateway Arch was built to commemorate President Thomas Jefferson’s push for continental exploration as well as St. Louis’ role in the westward expansion of the United States. But on October 28, 1965, all attention was riveted on the critical insertion of the final keystone piece that would complete the 630-foot structure.

The two “legs” of the Arch were built section-by-section over a five-year period. Cranes and derricks placed the prefabricated steel triangles into place – a total of 71 sections per leg.  When the two legs finally reached their full height, all that remained was the placement of the all-important eight-foot-long keystone section that would complete the Arch. 

On October 28, 1965, huge crowds lined both sides of the Mississippi Riverfront to watch as the final piece was installed.  Enormous jacks spread the monument’s two legs apart just wide enough to insert the keystone, aided by the spray of fire hoses that cooled down and contracted the surface of the south leg. Although the process took about three hours, most of the onlookers stayed around to watch the unfolding drama. When at last the keystone was inserted, the crowd cheered, bands played, and the stunning Gateway Arch soared into architectural and engineering history.        

To learn more about the building of the nation’s tallest monument, pick up a copy of The Construction of the Gateway Arch.  JNPA sells the book in The Arch Store, or online. 

And if you haven’t seen the award-winning documentary about the construction of the Arch – Monument to the Dream – you’re in for a treat.  It is shown daily in the theater at the Arch visitor center (advance tickets are recommended) or you can purchase a DVD of the movie at The Arch Store or online.