World's Largest Urban Bat Colony
Austin, Texas
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.
Across Congress Street stands a sculpture, "Nightwing," that celebrates the bat.
Bracken Cave in Texas is home to the world's largest colony of bats, but on land that for the most part is not publicly accessible. Another large, convenient-for-tourists bat colony is 15 miles north of Austin, underneath the I-35 underpass at McNeil Road, Round Rock. Over half a million there; wear a hat.