Sightseers in Chicago should keep their eyes open for cranes—the towering, metal kind.

The Windy City has more cranes for residential projects currently dotting its skyline than 11 other major U.S. cities, according to the Crane Index, a biannual survey of crane activity by Rider Levett Bucknall North America, a Phoenix-based construction consultancy.

As of November, Chicago had 56 construction cranes at work, 31 of which were being used for residential buildings, the survey found. Seattle had the second most residential cranes at 23, followed by Denver, with 10.

“There’s been a big increase, predominantly in the residential market,” said Paul Brussow, an RLB executive vice president.

In all, 33% of all cranes in the cities observed were dedicated to residential projects.