If you’re not an architect, or some other kind of construction savant, but are planning to see the Chicago Architecture Biennial, here’s some advice: grab one of the several daily free tours. In spite of the fact that CAB now has a half-dozen satellite shows in various neighborhoods, the main exhibition, at the Cultural Center, is massive, featuring projects by more than 140 international architectural firms and artists.

It’s not totally random, however. CAB staff consultant Garrett Karp, who was leading a tour when I dropped in last week, said the show is loosely organized from the bottom up, with mostly real, already-built projects in the main-floor galleries and successively more futuristic and speculative work on the upper levels.

You’ll also want to make time for a second collective project, “Vertical City,” in Yates Hall on the fourth floor. Fifteen architectural firms have reinterpreted the Tribune Tower competition, inspired by both the 1922 original contest and Stanley Tigerman’s 1980 redux. Each built an approximately 16-foot model, and all of them, plus similarly tall models of two of the 1922 designs, are on display.