Between the eerie glowing lights, the otherworldly cavernous spaces and the long strange trip it takes to get there, this subterranean museum feels like it could be located on an alien planet. The Salina Turda Salt Mines of Romania have been converted to the world’s largest salt mining museum, but this is no dry historical tour – there’s weird wooden architecture, a playground and even a ferris wheel.

All of the LED lights sticking out of those unusual architectural shapes at the center of the museum make it quite a sight from far above, when looking down into the mine plunging 120 meters (393 feet) into the earth. Visitors take elevators to each of the three museum chambers at various depths to see the restored equipment.

The sports arena, amphitheater, mini golf course and bowling lanes are reason enough to take a trip to the mine, but the caverns themselves are the main attraction. Uplighting shows off the amazing natural patterns on the excavated walls. There’s even a small subterranean lake with boats for rent.

The mines were first excavated in the 17th century and provided a vast wealth of salt for the Romans. The interior is totally free of allergens and almost entirely devoid of bacteria, and maintains a temperature of about 52 degrees with 80% humidity.