Thanks to its return to the real estate market, we get a glimpse of Frank Sinatra’s famous 3,200-square-foot New York City penthouse. Designed by Ol’ Blue Eyes himself in 1961 and serving as his primary residence until 1972, this spacious condo was dubbed a “glittering grotto in the sky” by fellow Manhattanite Andy Warhol. While its interior boasts four bedrooms, six bathrooms, massive window treatments and molded ceilings, the outside of Sinatra’s former dwelling offers two large wraparound terraces with stunning views of the East River. Moreover, thanks to a large renovation in 2008, this spectacular home – listed at $6 million USD – now features a contemporary glass staircase, marble fireplace and gourmet kitchen.