CHICAGO -- Tickets are on sale for Chicago's architecture cruises, which run May 3-Nov. 23.

The 90-minute tour, organized by the nonprofit Chicago Architecture Foundation, highlights 53 historic and architecturally significant sites including the Merchandise Mart, 333 W. Wacker, the Wrigley Building, the Tribune Tower, the Sears Tower and Marina City.

The cruise also includes significant buildings, sites and developments along the North Branch of the Chicago River such as the Chicago Tribune printing press plant; Goose Island; Riverbend and the clustered glass River Cottages.

The cruises take place on Chicago's First Lady Cruises 1920s-style yachts. They depart from the lower level and southeast corner of the Michigan Avenue Bridge at Wacker Drive, just north of Millennium Park (look for a blue awning).

Tickets are available via (312) 902-1500 or www.ticketmaster.com/rivercruise.