Albuquerque is that city in the Southwest where Route 66 intersects itself. The original Route 66 went up to Santa Fe and passed through Albuquerque on a north-south route along 4th Street. The route was changed and straightened in the late 1930s and aligned through Albuquerque on an east-west orientation along Central Avenue, which is Albuquerque's main street.
The two alignments meet downtown at 4th and Central, which has always been considered the heart of Downtown Albuquerque. Below is a pic of the intersection showing the Route 66 Crossroads clock tower that was installed in the mid-1990s. It was recently moved north two blocks after the former 1980s Crossroads Pedestrian Mall was taken out and 4th Street was reopened to vehicular traffic from Central Avenue to Civic Plaza.
Albuquerque today has the longest intact urban stretch of Route 66. It runs for about 17 miles along Central Avenue through the city. It is lined with historic neon signs, motels, trading posts and roadside attractions. Below is a famous pic from the 1960s of Route 66 signs in the Nob Hill and Highland areas. Also is a pic of one of the Route 66 gateways on Albuquerque's Westside. These were built at various points along the route in the 2000s to celebrate the 75th anniversary of Route 66 in 2001.