After being closed for more than a decade, the Illinois Caverns will finally be reopening to visitors.

The Illinois Caverns, which are located in Monroe County in southwest Illinois, were originally closed in 2010 by the Illinois Department of Natural Resources in an effort to slow the spread of white nose syndrome, a fungus that kill bats.

The fungus that causes white nose syndrome flourishes in caves. It spreads easily from bat to bat, but cannot be transmitted to other wildlife or humans. Researchers haven’t discovered how the fungus arrived in North America, but believe European visitors to caves accidentally carried the fungal spores on their clothes or gear.

The decision to reopen the Illinois Caverns was based on the small bat population that currently uses the caves and the low incidence of white nose syndrome seen in the Illinois Caverns.

For safety reasons, visitors must enter the caverns in groups of at least four, wear sturdy boots, wear a hard hat or bike helmet, and have at least three sources of light per person. Visitors are required to scrub their boots with bleach water before entering and exiting the cave.

The Illinois Caverns will be open from 9 a.m. to 4 p.m., Wednesday through Sunday. Entrance to the caverns is free.