You’ve probably heard of crocodile-infested golf course ponds before, but one unique golf course in Australia is home to an even greater threat that makes water hazards truly dangerous – sharks.

The 14th tee at the Carbrook Golf Club in Brisbane is a tricky one, as it’s close to a 21 hectare, 14-meter deep lagoon that happens to be the home of a dozen full-grown bull sharks. They’ve been around since the late 1990s, and even though the species is notorious for its aggressiveness, especially against humans, the bull sharks of Carbrook have become somewhat of a tourist attraction. The club even has a monthly tournament named after its unusual inhabitants, Shark Lake Challenge.

No one knows exactly how the bull sharks ended up in the Carbrook Golf Club, but the most popular theory is that they arrived during the Brisbane floods of the late 1990s. As the water receded, it is believed that six sharks found themselves trapped inside the course, but they managed to thrive and reproduce. Today, there are apparently a dozen sharks living in the lake.

But don’t sharks usually live in saltwater? Well, unlike most other shark species, bull sharks can survive in freshwater for long periods of time and have been spotted to travel over 1,000 kilometers up rivers like the Amazon or Mississippi. They aren’t strictly freshwater sharks, in fact, they prefer ocean coastlines, but they survive in it just fine.

“As a kid I used to go with my mates and we used to go looking for balls out on the golf course but that doesn’t happen anymore,” Carbrook Golf Course general manager Scott Wagstaff told Brisbane Times back in 2015. “If the ball goes into the shark lake, it is generally never to be seen again, there would be quite a lot of balls in that lake as no one has been in there in 15 years.”

Carbrook is the world’s only golf course with sharks, and they are a big draw for both members and visitors. Some of the sharks are about 3-meters-long, and even though human-bull shark encounters in freshwater are rare, there are signs warning people that the lagoon is home to the world’s most aggressive sharks.

“It’s hard to explain the feeling of seeing an eight-foot shark cruise past you on the edge of the lake while your golfing, it’s pretty cool to see,” Wagstaff said. “They are beautiful animals to see close, I have become a bit of an admirer in my time here, they have got that reputation of being aggressive and dangerous, and that is probably rightly so, but what I have seen of them is that they are very graceful, far from aggressive.

Although it has some scary water hazards, Carbrook is not the world’s most dangerous golf course. That title goes to the course at Camp Bonifas in South Korea.