Just before sunset each night, nearly 80,000 Purple Martin birds can be seen flocking to an area of downtown Nashville, near Interstate 24 and Crutcher Street.
For the past few weeks, the birds have been coming to the area to sleep and make quite an entrance when they arrive.
"You can see martin's coming in from all directions, some really high, some down low and a lot of them are swirling around in tornado type behavior and then they dive down thousands at a time down to the roost on the side of the Interstate," Tennessee Wildlife Resources Agency state ornithologist Scott Somershoe said.
Spectators have also been flocking to the area to catch the bird's nightly show.
"It would be wonderful [to see], I haven't seen a roost like this before," Russell Elrod told Nashville's News 2.
Purple Martins are the largest swallow in North America.
In years past, the birds roosted in an area closer to LP Field. This is the first year the birds are at the location off Crutcher Street.
"There's really two [large] roosts in Tennessee; there's one on Tim's Ford Lake and the one here in Nashville," Somershoe said.
During the day, the birds fly as far as Kentucky but return to their spot off the interstate each night.
The birds will likely take off to Brazil for the winter during the first week of September.
The best time to view the Purple Martins roosting is about a half an hour before sunset.
To get to the location, take the Shelby Avenue exit off Interstate 24, make a right onto South Fifth Street and go south about two blocks to Crutcher Street.