The Castillo St. Bridge
It was a bright sunny day in New Mexico, the sort of dry, hot day that is the hallmark of the American Southwest. The intense sun reflected off the light tan buildings, blinding anyone out in the noonday sun without sunglasses. On a small attractive bridge situated in the heart of Santa Fe, two men met. One was in short sleeves and khaki slacks, of average height, slim and somber, with steel-rimmed glasses and clip-on sunglasses. The other was short and dumpy, incongruously wearing a fedora and a raincoat. He was dressed inappropriately for the desert heat, and was squinting against the bright sun and its reflection off the bone-dry buildings.
They came together on the bridge, in full view of anyone who would care to glance their way. No one noticed them ─ they were merely two of the many strangers that had appeared in Santa Fe during the war years. However, on this June day in 1945, this apparently innocent meeting was not a casual happenstance. The taller of the two men (Klaus Fuchs, below) handed an envelope to the short, fat easterner.

It contained the principal elements of the design of the atomic bomb.
This was not the first time the two had met. Five or six times prior to the meeting on the bridge in Santa Fe, the taller man had given the shorter one envelopes containing scientific documents. These other meetings had been in New York. Most of them were brief, lasting only a few minutes. The two men did not really know each other. The short man ─ the courier ─ was known to the taller man only as “Raymond.” In New York, four days after the meeting in Santa Fe, the courier delivered the envelope to his Russian contact, just as he had delivered similar packets of secrets after other meetings.
Aiuto, Russell. 2005. The First Atom Bomb, http://www.crimelibrary.com/terrorists_spies/spies/fuchs/1.html
The man known as Raymond was actually Harry Gold. (Shown Below)

The collaboration that produced the bombs so quickly also allowed information to leak to the Soviet Union. Most of that information passed between Klaus Fuchs and Harry Gold on the Castillo Street Bridge in Santa Fe.
Castillo Street was one of several streets replaced by the development of the Paseo de Peralta loop around Santa Fe's downtown. But that hasn't hampered the development of local legend.
A block to the east, on Delgado Street, is a very similar bridge over the Santa Fe River. The most prevalent local story is that the secrets were passed under the Delgado Street Bridge.
Miller, Jay. 2005. 7-18 Trinity 2, http://insidethecapitol.blogspot.com/2005/07/7-18-trinity-2.html