Here are some of the ancient observatories that enabled people to learn a great deal about space long before the invention of the first telescope in the early 17th century.
Ulugh Beg Observatory in Samarkand, Uzbekistan
The Ulugh Beg Observatory was built in the 1420s at the behest of Ulugh Beg, the grandson of Tamerlane. The structure is the last of its kind dating from the Islamic medieval period. Astronomers including Jamshid al-Kashi, Ali Qushji, and Ulugh Beg himself worked at the observatory. Mostly known for his scientific pursuits, Ulugh Beg was an unpopular ruler. Eventually, his son tried and then beheaded Ulugh Beg after losing several battles in 1449. The observatory was destroyed in the same year, and the other astronomers were exiled. Later, Ali Qushji published Ulugh Beg’s extensive star catalog containing at least 1,018 stars. The ruins were discovered in 1908, and the observatory was rebuilt in 1970, operating as The Ulug Beg Observatory Museum.
Chaco Culture National Historical Park in Nageezi, New Mexico
El Caracol in Chichen Itza, Mexico
El Caracol, meaning snail, is one of the oldest observatories in the world. The structure’s cylindrical design enabled the Mayan astronomers to observe the sky in 360 degrees.
Radkan Tower in Iran
Inıtially thought to be a tomb, the Radkan Tower is a 13th-century observatory built by Nasir al-Din Tusi, one of the greatest Persian scholars of the century. The structure has 12 walls, corresponding to the 12 months of the year. 36 exterior columns over the dodecagon base create a cylindrical structure topped by a dome. On solstice and equinox days, the sun shines perfectly through the doors on opposite sides of the tower. Moreover, the structure can determine the beginning of the four seasons, leap years, and the Nowruz (the Iranian New Year).
Over 7500-Year-Old Carahunge Observatory in Sisian, Armenia
Carahunge, or Zorats Karer, is a circle of 223 Neolithic stones with northern and southern arms in the village of Sisian, Armenia. Although the exact purpose of the stones is uncertain, the holes on several stones suggest that the site was an observatory.
Goseck Circle in Germany
Goseck Circle dates from 4900 BC and probably remained in use for around 200 years. Therefore, the site may be the oldest Neolithic circular enclosure in Central Europe. Archaeologists believe that the Neolithic farmers used the circle as a calendar. The discovery of cattle skulls and human skeletons also suggests a ritualistic use for burial or sacrifice. After starting excavations in the early 2000s, archaeologists reerected wooden stakes marking the original shape of the enclosure.
Callanish Stones in Outer Hebrides, Scotland
Although the exact purpose of the 5000-year-old Callanish Stones is uncertain, the recent excavations suggest that the 12-foot-tall megaliths acted as a kind of astronomical observatory or a celestial calendar.