Lake Ongeim'l Tketau, better known as 'Jellyfish Lake', is located in one of the islands in Palau, and is one of the top tourist attractions in the western Pacific Ocean.
The lake is about 400 metres long and 30 metres deep, and has been named after the golden jellyfish that live in it, which entered through a small tunnel that connected the lake to the sea.
The lake's golden jellyfish, Mastigias papua etpisoni, is a unique subspecies that can only be found there and is completely harmless. They have stinging cells but their sting is hardly noticed.
In 2005, the lake's jellyfish population reached a record high of 30 million, but drought and climate change have reduced the number of jellyfish, and they nearly disappeared in 2016.
This population decline, however, was not only due to climate change. A study by the Government of Palau found high concentrations of substances from sunscreen lotion in the lake's water, substances which cause irreversible ecosystem damage.
Now, after being closed for two years, it is once again open to visitors, albeit there are some rules for those that wish to swim in the lake: biodiversity must be protected, nothing can be taken from the aquatic ecosystem as a souvenir, and sunscreen lotion may not be used.
Nevertheless, scuba diving is not allowed, because the anoxic layer that begins at about 14 metres of depth contains high concentrations of hydrogen sulfide which can be harmful to humans.
Would you dare to dive among the jellyfish?