The jellyfish are back, and Palau’s Ongeim’l Tketau — known as Jellyfish Lake — has reopened to tourists after nearly two years.

The popular snorkeling site took a major hit in 2016 during a drought caused by an El Niño event in Palau. Sam’s Tours, voted as Palau’s top dive operator in Scuba Diving's 2019 Readers Choice Awards, announced that it was returning to Jellyfish Lake in late December.

“Two years ago, during a drought caused by an El Nino event, the medusas disappeared from the lake due to abnormal conditions such as high temperatures and salinity,” said Sam’s Tours in a Facebook post. “In late November 2018, Coral Reef Research Foundation reported nearly 1 million jellyfish as well as the return of the moon jellyfish (Aurelia aurita) that vanished in 2009.”

The lake hit an all-time high with 30 million jellyfish in 2005, according to CNN. The jellyfish have weak nematocysts, allowing humans to float and snorkel in the lake without being stung.

The government officially closed the lake, which is located on Eil Malk in the Rock Islands, in 2017 but many operators ceased their Jellyfish Lake tours in 2016.

While Ongeim’l Tketau is the most famous example, there are other similar jellyfish lakes around the world. Check out this video from Indonesia’s Kakaban Island, where you can encounter four species of jellyfish.