The Guardian Building

A treasure hidden in plain sight, this 40-story architectural gem is a quirky Art Deco-style orangey brick-terra-cotta-limestone skyscraper. Built in 1929 and renovated to pristine condition, it includes a soaring cathedral ceiling, giant tile mosaics depicting Michigan history, and intricate tiles and stained glass designed around Art Deco and Native American themes.

Tip: Two blocks away is Campus Martius Park, which offers lunchtime jazz in summer and ice-skating in winter.

Admission: Free. Tours conducted Monday through Friday at 10 a.m. and noon.