The Great Smoky Mountains National Park will be using an online lottery system once again for tickets to its annual synchronous firefly event at Elkmont.

The park used a lottery system for the first time in 2016. 

Dates for this year's event will be announced on April 25, park spokesperson Dana Soehn confirmed. 

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This year's ticket lottery will open on April 28 and remain open through May 1. Ticket winners will be notified on May 10. 

Elkmont is one of the few places in the world where you can see the Photinus carolinus, the special kind of firefly that flashes in sync.

MORE: Synchronous fireflies draw thousands to GSMNP

The event has become so popular over the years that the park has had to take steps to limit the number of people that could view the fireflies each night.

In 2016, 1,800 people were selected out of more than 20,000 applicants. 

Soehn added that there will be the same amount of tickets available in 2017. 

There is no fee to enter the lottery, but if you're picked there will be a $2.75 reservation fee for the parking pass to the Sugarland Visitor Center. Guests will then take shuttles from there to the Elkmont campground where the firefly viewing takes place.