What is the name of the Los Angeles interchange that was the world’s first stack interchange and once carried Route 66?

The Four Level Interchange in Los Angeles was the world’s first stack interchange and once carried Route 66.

The structure stands at the northern edge of downtown Los Angeles, where U.S. Route 101 and State Route 110 meet. Its multiple levels let traffic move between crossing freeways without relying on a conventional cloverleaf layout.

Construction was completed in 1949, although the interchange did not fully open until 1953. The north-south road was originally associated with U.S. Route 66 and U.S. Route 6 before later numbering changes removed those designations.

The interchange is also officially known as the Bill Keene Memorial Interchange, a name adopted in 2006. However, Four Level Interchange remains the common historic name and the one most closely associated with its pioneering design.