The Regional Park of Sirente-Velino.
The Sirente-Velino Park was created by the Region of Abruzzo in 1989. Its territory borders on Lazio to the west, on the Plain of Fucino to the south and on the river Aterno to the north. It includes Monte Velino, whose 2,468 metres make it the Apennines third highest peak, and the massif of Sirente, which is formed by a single almost straight ridge of about 20 kms and whose topmost peak, called Monte Sirente, is 2,348 mts high.
Though the Velino and Sirente are divided by the fault bounding the Altopiano delle Rocche, they show the same geological and tectonic structure. According to Dionysius of Halicarnassous, the name "Velino" comes from the Greek word Hetos, which means "swamp". Though its present barren aspect makes it impossible to believe , at the beginning of the Quaternary period the massif contained a series of high altitude lakes, whose traces give the landscape an enchanting look. The karst phenomena are especially noticeable here. They produced the Grotte di Stiffe, in the district of S. Demetrio ne' Vestini. An underground river, lei by the sink-holes water of the karst plateau of the Rocche, runs across the caves. Inside you can admire several small lakes and falls up to 20 metres high. In the various sections of the caves, besides the stalactites and stalagmites, you can enjoy the marvellous visual and sound-effects produced by the water. Outside you can admire the falls created by the water flowing out from the caves. Guided tours to the Grotte di Stiffe, by the L'Aquila Spelaeological Group, are available every day in July and August, but only on Saturday and Sunday in the rest of the year.