Pamukkale and Hierapolis are awe-inspiring sites that exist side by side in the Denizli Province of southwestern Türkiye. In 1988, they were simultaneously recognized as one of only 39 mixed UNESCO World Heritage listings, meaning they contain both natural and cultural significance, in the entire world.First, let’s visit the surreal travertine landscape of Pamukkale, which is continuously fed by primordial, mineral-rich springs perched on a 200-meter-high cliff. Over a sizeable period of time, the springs have created the most delightful series of petrified limestone waterfalls and terraced basins. This natural beauty is known as Pamukkale, the “Cotton Palace.” Geographically, it is the large amount of calcium carbonate, or limestone, deposited near the emerging underground thermal springs that is the major factor in the formation of Pamukkale. The terraces descend 160 meters over a lengthy run of approximately 2,700 meters, carved over approximately 14,000 years. The calcium-laden water ensures the continued shimmering white appearance of Pamukkale’s terraced thermal pools.On the summit plateau above Pamukkale sits the multi-millennia-old city of Hierapolis, believed to have been founded in the early second century BC. The large, three-arched stone gateway at the city’s entrance was built in 83 AD in honor of the emperor Domitian. Hierapolis’ main thoroughfare, known as Colonnade Street, is a beautiful example of a Roman town avenue. Approximately one mile in length, running north to south, it is lined with pillars and the remains of many Roman-style buildings. The avenue leads to another stone gateway at the far end.One of the highlights of Hierapolis is the ancient city’s most well-preserved structure, the Roman theatre. The theatre was built to seat approximately 15,000 people, who would come to see concerts and plays, religious ceremonies, and competitions. The Romans built baths at Hierapolis in the third century, in the classical Roman architectural style, employing the use of large stone blocks. The main thoroughfare features a hot spring fountain, and the baths are still open to the public. On a large hillside near the site of Hierapolis is the church dedicated to Saint Philip, constructed in the 5th century, which includes the octagonal Byzantine-style central chamber containing the tomb of Saint Philip.