The cavern is large enough to contain the entire St. Peter's Basilica of Rome.
Two long pendulums attached to the cave ceiling function as inclinometers to measure the Earth's crustal tides.
The cave temperature remains constant at approximately 11 degrees Celsius year-round.
It is a 'fossil' cave, meaning it no longer contains the active underground river that originally carved it.
The cave floor is covered with significant sediment deposits that provide historical climate data.
It was first fully explored in 1897 by members of the Alpine Club of Trieste.
Grotta Gigante is a massive karst cavern near Trieste, Italy, recognized by the Guinness World Records as one of the largest single-chamber tourist caves in the world. The primary chamber, known as the Great Cavern, measures 107 meters in height, 65 meters in width, and 130 meters in length. Located within the Trieste Karst plateau, the cave is managed by the Alpine Club of Trieste. Visitors descend a series of 500 steps to reach the base of the cavern and ascend via another set of stairs to complete the circuit. The environment is home to unique cave fauna, including the specialized crustacean Monolistra spinosa. Scientific monitoring equipment inside the cave measures micro-movements of the Earth's crust. It is a show cave accessible via guided tours that highlight the geological formation and history of the karst landscape.
From the center of the cavern floor looking directly up at the ceiling lights.
Wear a warm jacket regardless of the outside temperature, as the cave is cold and damp.
Use sturdy, non-slip footwear to safely navigate the 500 steps down and up.
Check the official website for group tour availability if you are traveling with a large party.
Do not underestimate the physical effort required to climb back up the 500 steps; avoid visiting if you have severe mobility or heart issues.
Closed on Mondays throughout the year except during specific holiday periods; closed on January 1st and December 25th.
Do not touch the stalactites or stalagmites; stay with the guide at all times; no flash photography allowed.
