The Southwest Freeway was one of the few legs of what would have been a giant, destructive double loop of interstates planned for Washington, DC. Thankfully, the interstates were stopped before any more damage could be done. See the church below in the background here.
Sadly, it was too late to salvage the connectivity of Southwest to the rest of the city; the area remains isolated and largely out of the public consciousness of the city.
See its mate, the Southeast Freeway.