Here’s a very cool find from 1969: the story of Lake Point Tower, architects George Schipporeit and John Heinrich’s sensuously curved residential tower at Ohio and Lake Shore Drive.

The documentary, Lake Point Tower: The Story of Building a Building—ok, not the catchiest title, but still—tells the start-to-finish story of the icon: a building “a little bit different,” as Schipporeit describes it in the film. The video comes courtesy of Lake Point Tower’s YouTube channel created by residents Paul LeRoux and Gary Wilson. The spot features a nice collection of clips related to the building.

Watching it 40 years on, the documentary reminds us what a sensation this building caused was when it was completed in 1968. It was Schipporeit and Heinrich’s first commission—and it was a winner. The pinwheel floorplan of the 70-story building—a take on Ludwig Mies van der Rohe’s unbuilt glass tower of the 1920s—broke up the modernist glass box that was prevalent then (Schipporeit and Heinrich had been Mies’ students). The tower rests on a podium that contains a two-and-a-half-acre park designed by the great landscape architect Alfred Caldwell. And for a spell, Lake Point Tower was the tallest residential building.

Schipporeit ably narrates the documentary and throws out some great details including how the tower’s shape allows each resident a view of Lake Michigan; the building weights 300 million pounds; soil tests on the site revealed 20 ft of Chicago Fire rubble and engineers had to drill down 90 ft to hardpan in order to build. There is some pretty good construction footage, also.

Here the building begins to really take shape and at 5:18, there are some pretty groovy—no other way to describe it—views of the completed interiors:

Schipporeit is a professor of architecture at IIT. Heinrich died in 1993 at age 65.