HANNIBAL, Mo. (AP) — Cave enthusiasts are gathering in northeastern Missouri this week for a national cave convention.

The Herald-Whig reports that the National Caves Association is holding its 52nd annual convention in Hannibal. The last time the event was held in the city was 1979.

Representatives from more than 50 caves are expected to attend the five-day event, which ends Friday.

The convention is being held at the Mark Twain Cave Complex. Attendees will tour the cave, learn how it operates and view educational presentations.

The National Caves Association was founded by a group of show cave owners in 1965. The association now has more than 80 members who work together to promote the show cave industry.