World's Largest Urban Bat Colony
Crowds gather nightly to watch 1.5 million Mexican free-tailed bats shoot out from under the Congress Avenue Bridge. Standing atop the bridge, or down below (wear a hat), visitors provide condemned mosquitoes a last meal while waiting for the bats to make their entrance.
Two thumbs up to the Austin American-Statesman for allowing the use of their parking lot, and their grass to hang out on.
Across Congress Street from the Statesman stands a sculpture, "Nightwing," that celebrates the bat.
Another convenient-for-tourists (but smaller) bat colony is reported 15 miles north of Austin, underneath the I-35 underpass at McNeil Road, Round Rock. Again, wear a hat.