Formed thousands of years ago by the activity of the Pivka
River, the Postojna Caves known today cover a network totalling
more than 12 miles (19 kilometres) - which makes it the largest
karst rock cave in Europe. The caves were discovered in the late
18th century and were never mined, so they could quickly be opened
to the public. The first visitors came in 1819.
One of the elements that make caves so attractive to visitors is
the formations (including stalagmites and stalactites) resulting
from deposits of calcium carbonate. Another reason for the caves'
early success was because they were the first to use a number of
features. For example, it was lit with electricity in 1884 -
preceding even Ljubljana, Slovenia's capital. Railway lines were
laid in some of the caves in 1872, at a time when many working
mines did not use rail traction. The labyrinth of caves can still
be entered on the small electric railway, which takes you into the
heart of the caves, allowing you to explore the larger caverns on