Borgio Verezzi Caves, Show cave in Borgio Verezzi, Italy.

Borgio Verezzi Caves form an underground system extending about 800 meters beneath the surface with natural chambers and small pools. These pools were created by the Rio Battorezza stream, and the rock walls display mineral deposits that create colorful patterns throughout the passages.

The cave system was discovered in 1933 and contains prehistoric bone remains dated between 500,000 and 750,000 years old preserved in its chambers. These archaeological finds reveal that early humans inhabited this area during the distant past.

The name Valdemino comes from the valley where the caves lie, on the outskirts of Borgio. Since the tourist route opened in 1970, visitors have walked the 800 m path past small lakes fed by the Rio Battorezza. Minerals give the walls white, yellow and red tones, which earned the caves the nickname "the most colorful show caves of Italy".

Guided tours run throughout the year, and the temperature inside stays constant at around 16 degrees Celsius (60°F) regardless of weather outside. Since it remains cool year-round, visitors should bring a jacket even on warm days above ground.

Among the cave's many straws is the longest known in Italy, a hollow formation 2.5 m (8.2 ft) long. Such straws grow as water drips through their hollow centre and deposits calcite at the tip, so the tube lengthens drop by drop.