Puglia is a region of Southern Italy bordering the Adriatic Sea in the east, the Ionian Sea to the southeast, and the Strait of Otranto and Gulf of Taranto in the south. It borders Molise to the north, Basilicata and Campania to the west, and includes the provinces of Bari, Brindisi, Foggia, Lecce and Taranto. Its southernmost portion, known as “Salento peninsula”, forms a high heel on the "boot" of Italy. Its capital city is Bari. The region forms a sort of narrow rectangle, stretched from north-west for about 350 km, which juts out between the channel of Otranto (Adriatic Sea) and the gulf of Taranto (Ionian Sea) with the Salento peninsula. More than half of the territory is flat, the remaining portion is mostly hilly. Almost the whole region is made up of limestone rocks in which are found evident Karstic phenomena of surface, as well as of depth. The Caves of Castellana, one of the most spectacular underground tourism sites of Italy, which provides the opportunity to observe grandiose karst formations of stalactites and stalagmites, is located in this region (the Murge Plateau). Some of the various areas of the caves are the Black Cave, the White Cave, the Cavern of Monuments, the Cave of the Precipice, etc. Puglia boasts a coastal development of about 800 km and its morphology is somewhat diversified. To the northeast is the promontory of the Gargano. The stretch of land that surrounds it is almost everywhere high and rocky, with a flat area at the coastal lakes of Varano and Lesina. The Gargano is the only significant receding area of the Apulian Adriatic coast, which is morphologically varied: it is low and sandy in large stretches, whereas minute inlets in other stretches enliven it. Tourism in Puglia has great potential and keeps attracting strong currents of travellers since the eighties. The main areas of interest are seaside tourism, art, places of naturalistic interest and pilgrimage. There is a great wealth of Romanesque and Baroque architecture in the region that is not yet well known to international flows. The most famous resorts for summer and seaside tourism are the Tremiti islands and the Gargano centers (Peschici, Pugnochiuso, Mattinata, Rodi Garganico, Vieste). The most popular pilgrimage centers are Monte Sant'Angelo and San Giovanni Rotondo. The places of naturalistic interest are the Castellana Caves; the historical and monumental centers (Ostuni, Trani, the historical nuclei of Lecce, Taranto etc.); and the Murge plateau, which is known for its spectacular "trulli", often refrred to as the ”Trulli di Alberobello”. The latter is one of the most stunning examples of Italian popular architecture, which is represented by the ancient stone houses with cone shape. The trulli have been included by the UNESCO in the World Heritage List, as a World Heritage Site.