The Derinkuyu underground city (Cappadocian Greek: Μαλακοπή Malakopi) is an ancient multi-level underground city in the Derinkuyu district in Nevşehir Province, Turkey, extending to a depth of approximately 60 metres (200 ft). It is large enough to have sheltered as many as 20,000 people together with their livestock and food stores. It is the largest excavated underground city in Turkey and is one of several underground complexes found throughout Cappadocia.

The lake basin formed as a result of volcanic activity; specifically it is classed as a maar lake. There is still geothermal activity in the area, which has given rise to hot springs around the lake. In recent years, the geothermal waters have been pumped up to nearby hotels for use in their hot baths. Lake Nar is particularly known for its scientific importance. It is home to a newly-described species of microscopic diatom algae called Clipeoparvus anatolicus. Nar lake waters undergo a remarkable change between different seasons. In winter, the lake water is cold from top to bottom. As the temperature increases in the spring, the lake water divides into an upper half which is warm (epilimnion), while the lower half (hypolimnion) stays cold and lacking in oxygen. An abundance of planktonic algae (or plankton bloom) in early summer changes the water chemistry and leads to the precipitation of calcium carbonate.

The canyon was formed in prehistoric times by the Melendiz Çayı. It lies between the villages of Ihlara in the southeast and Selime in the northwest. At the north end of the village of Ihlara, there is a stairway with almost 400 steps, which descends over 100 m down into the canyon. From the 7th century AD, the valley was settled by Byzantine monks who dug their houses and churches out of the tuff stone, which had been deposited by the eruptions of Mount Hasan. The earlier Greek name, Peristrema (Περιστρημα; winding round) of the village of Belisarma which is located about halfway along the valley from Ihlara to Selime, gave its name to the valley as well.

Lunch in Local Restaurant.

Selime Monastery is an astonishing rock-cut construction and the largest religious structure in the Cappadocia region with a cathedral-sized church cut directly into the volcanic tuff. Inside, original frescoes can be found although some have been damaged by weather. Signs of early civilizations are also present at the ancient site: Hittites, Persians, Romans, Early Christians, Byzantines, Seljuk Turks and Ottomans are some of the many inhabitants to have settled here. The church is separated into 3 sections by two rock columns. Kitchens and stables are also present as well as monks' living quarters which are adorned with time-worn frescoes. Selime Monastery is said to date back to the 8th or 9th century BC. The upper section mildly resembles a fortress with well-preserved walls and trenches as well as steep rock staircases and hidden passageways. In the 10th/11th century, the Monastery was converted to a Caravanserai, a refuge for travellers and tradesmen.