section_path: History/Middle Ages
section_name: Middle Ages
paragraph_text: Middle Ages
  
  Shāh Abbās Arch (Persian: طاق شاه عباس), also known as Kurit Dam, is the thinnest arch dam in the world and one of the oldest arch dams in Asia. It was constructed some 700 years ago in Tabas county, South Khorasan Province, Iran. It stands 60 meters tall, and in crest is a one meter width. Some historians believe the dam was built by Shāh Abbās I, whereas others believe that he repaired it.
  
  In the Netherlands, a low-lying country, dams were often built to block rivers to regulate the water level and to prevent the sea from entering the marshlands. Such dams often marked the beginning of a town or city because it was easy to cross the river at such a place, and often influenced Dutch place names. The present Dutch capital, Amsterdam (old name Amstelredam), started with a dam on the river Amstel in the late 12th century, and Rotterdam began with a dam on the river Rotte, a minor tributary of the Nieuwe Maas. The central square of Amsterdam, covering the original site of the 800-year-old dam, still carries the name Dam Square.