From spring through November, Tucsonans have the opportunity to watch thousands of Mexican bats darken the sunset sky like a crazy kinetic cloud. Bridges at Pantano Road and Broadway Boulevard, Ina Road over the Santa Cruz, and Campbell Avenue at the Rillito provide bats with an ideal place to hang out and chill in a cavelike environment. Then at dusk, they exit en masse to eat insects. The twilight flights are quick, so pay attention. At first, a few bats will emerge, flittering and fluttering, and then the rest will pour out--and before you know it, the show is over.