Be patient! And don't be deterred by the stinky-yet-slightly-corn-tortilla-like smell. We got there around six o'clock in early September and the bats didn't really start flying until about 7:15. Basically, wait until it's dusk and any photos you take are too dark. So just enjoy it and don't try to take pictures. We parked in the business park where they had guest spots for up to an hour, then walked along the canal until we saw the bridge/cave area. Pretty easy to get to. Super worth it if you like nature things like this.