The world's skinniest skyscraper is almost completed. I toured its first luxury condo - take a look inside the NYC tower that's 24 times taller than it is wide.

A bevy of super-tall, glossy skyscrapers is rising along New York City's Billionaires' Row, an area south of Central Park that's home to some of the most expensive real estate in the city.

There's Central Park Tower, which recently became the tallest residential building in the world. Then there's 220 Central Park South, which broke real-estate records when billionaire hedge fund manager Ken Griffin paid $238 million for a spread of condos. Both towers are expected to be finished sometime in 2020.

And now, nearing completion is 111 West 57th Street, which has the distinction of being the world's most slender skyscraper. The 1,428-foot tower is 24 times taller than it is wide and has only one residence per floor.

The skinny skyscraper, which was developed by JDS Development Group, Property Markets Group, and Spruce Capital Partners, is expected to welcome its first residents in the summer of 2020.

Take a look inside the first finished condo at the world's most slender skyscraper.