This is another of those "last man on Earth" movies. It's actually almost exactly like an I Am Legend adaptation, except that there are no monsters. It's just Harry Belafonte running around a deserted Manhattan shouting for the first hour or so. Actually, the new I Am Legend uses a lot of elements from this, including the art collecting and the talking to mannequins.
About halfway through, a woman shows up, and it's a white woman, which generates a small amount of tension. And then another guy shows up, and there's some by-the-numbers tension, followed by a surprisingly unexciting gunfight in abandoned New York streets. And then there's a fairly random ending.
The parts of the movie where Belafonte is trying to come to terms with everybody on Earth being gone are pretty good. Unfortunately, he takes a really long time to figure out that everybody's really gone. Movie Shorthand for "empty city" is "a bunch of discarded newspapers blowing through the shot like tumbleweeds", so he had plenty of opportunity to pick one up and find out what happened to everyone.