For just two weeks a year — late May to early June — a firefly mating ritual plays out in the Great Smoky Mountains. It’s just literally thousands and thousands of fireflies coming together to put on a synchronized light show.
This is exactly as awesome as it sounds, so seeing the phenomenon for yourself is no longer as simple as just showing up - it’s way too popular for that. These days, there’s a lottery system in place that will grant parking passes to 1,800 lucky drivers and presumably as many people as they cram in their vehicles. The lottery will be held from noon PST on April 29 to 8 p.m. PST on May 2. However, tickets are expected to run out, like, immediately. So, if you’re serious about this, make sure you’re online and refreshing furiously the moment the clock strikes noon on Friday. Think of it like a chill Coachella. The shuttle-operating period will run from May 31 to June 7; you’ll be notified by May 10 if you got a ticket.
You can see more info about the lottery here.
The 1,800-car limit is largely to protect the fireflies themselves, though it also helps cut down on congestion and other unpleasantries.
According to the National Park Service, the Great Smoky Mountains are home to 19 species of fireflies that we know of. Synchronous fireflies (Photinus carolinus) are, as the name suggests, the only ones who put on this sort of show. Different species have different flash patterns, which help males and females identify suitable partners. As to exactly why these fireflies flash in unison once a year, we still don’t really know. For now, at least, we’ll just have to enjoy the mystery (if you can get a ticket).