Fascinating network of underground caverns, whose weird stalactites and stalagmites conjure up mysterious images of Heaven and Hell.

If you only have time to visit one set of caves on the east coast, this is the one to see. Now that they are a sanitised tourist attraction, it is hard to imagine how French geologist Edouard Martel felt when he first stepped into these caves, dark, mysterious and terrifying, in 1876. In fact they had been known about for centuries - Jaume I found 2,000 Arabs hiding here with their cattle during the Christian conquest and they were later used by hermits, pirates and smugglers - but it was Martel who first studied and chronicled these grottoes, 46m above the sea at Cap Vermell, at the instigation of Archduke Ludwig Salvator. Another early visitor was Jules Verne; the caves are said to have inspired his Journey to the Centre of the Earth. The guided tour comes with special effects and the various chambers are given Dantesque names - Hell, Purgatory, Paradise. The descent into Hell is swifty followed by a son et lumiere display. Stalactites point down from the mouldy roof like daggers, somehow defying gravity. One of the chambers is as large as the nave of Palma Cathedral, and the Queen of Pillars, a stalagmite 22m tall, could almost be a Gothic column. It is growing upwards at the rate of 2cm every 100 years, in another 5,000 years or so it will be joined to the ceiling. You emerge from the caves to a view of the sea, framed by the cavern entrance. Disabled visitors and others with limited mobility will find the staircases in here particularly difficult. All visitors should be sensibly shod, as the floor can be slippery.