Aillwee Cave, Doolin
Some of the best caves in Ireland (or as the tourist info puts it "Ireland's premier showcave" - whatever that may mean!) the Aillwee caves are definitely worth a visit
If you think the Burren is impressive looking above ground then check it out below where the caves are full of spectacular rock formations.
The caves are open all year round (from 10.00am to 6.00pm with last admissions 30 minutes before closing) and cost €7.50 for adults (€4.50 for children with reductions for students & OAPs). Family tickets are also available