This combination railway bridge and traffic underpass, made of concrete and costing $1 million (half of which was provided by the federal government), was built between 1934 and 1936 on the site of the former Trinity River channel, which had earlier been moved westward and placed behind levees to reduce the possibility of flooding.

Designed in the "Art Deco" style popular during the 1930s, the underpass, through which Dallas' three principal thoroughfares (Commerce, Main, and Elm streets) converge, was formally dedicated on May 1, 1936.

A panoramic view of Dealey Plaza may be enjoyed from a paved footpath atop the underpass, which is accessible from the Sixth Floor Museum parking lot.