Now, it bridges an apartment that now serves as an office-slash-bedroom at 61 E. 77th St. to the duplex penthouse — and into its living room with 18-foot ceilings and a fireplace.

That’s just a bit over eight miles per hour. The design is optimized to work between tall buildings, which produce turbulence patterns that affect the effectiveness of other urban turbine designs.

Manhattanhenge happens when the sunset aligns with NYC's street grid. The sun appears to set perfectly between buildings in the city skyline. The phenomenon takes place on four days a year -- two ...