Just north of Trieste is Borgo Grotta Gigante, home to one of the world’s largest tourist caves, second only to La Verna cave in south-western France. The cave, aptly named Grotta Gigante (Giant cave) is also known as Riesengrotte or as Grotta di Brisciachi, and is located on the Italian side of the Karst. Its central cavern is 107 m (351 ft) high, 65 m (213 ft) wide and 130 m (430 ft) long. It is around 10 million years old.
The cave was first explored by Antonio Federico Lindner in 1840. He had hoped to tap into the Timavo River in order to provide a supplementary water source for the rapidly growing city of Trieste, but that was not to be. Exploration continued in following years, in particular by the daring and adventurous Giovanni Sigon, considered the father of Triestine spelunking. In 1890, a second opening was discovered and the Club Touristi Triestini undertook a complete exploration of the cave, eventually uncovering a third entrance. In 1897, it was fully mapped by Andrea Perko, a leading speleologist who compiled an important report on his archeological findings. In 1905 work began on steps leading to the floor of the cave and it was opened to the public on July 5 1908. On that occasion, the cave was lit with thousands of candles, regular and acetylene torches and a chandelier with hundreds of votives while the town band played Richard Wagner’s Siegfried of the Der Ring des Nibelungen, one can only imagine the spectacle! Sightseeing in the cave only really began in 1957 when it was wired for electrical illumination.
It is a constant 52 degrees in the cave and humidity is at 96%. There are many large stalagtites and stalagmites, several of exceptional beauty and size. A main feature of these stalagmites is their “dish-pile” appearance, formed by water dropping from up to 80 meters depositing calcium carbonate over a wide area. The tallest stalagmite is Colonna Ruggero which is 12 meters tall. Their rate of growth is 1 mm per 15 yrs.
There are 500 steps leading down to the lowest point of the cave (which means there are 500 coming back up!). The tour takes about 1 hour and the distance covered is just under 1 km. Throughout the year, special events and concerts take place in the cave, some of the more famous are the annual parties like Halloween, San Nicolo (Trieste’s Santa Claus usually the first week of Dec.) and the Befana who visits in the first week of January. There are also wine tastings, tightrope walkers and acrobatic performances and of course many science-focused gatherings. Grotta Gigante is open year round but check the website for specific hours as they change.
Località Borgo Grotta Gigante 42/A – Sgonico (Trieste)
tel. & fax +39 040/327312