In 2007, Clive Ruggles and Ivan Ghezzi identified one of these structures built 2300 years ago at Chankillo by the Casma-Sechin culture of Peru.
In 2007, Clive Ruggles and Ivan Ghezzi identified one of these structures built 2300 years ago at Chankillo by the Casma-Sechin culture of Peru. Another ancient one of these things called the Cheomseongdae was built by Queen Seondeok in South Korea. Five of these structures calledthe Jantar Mantar, one of which has the Vrihat samrat yantra, were built by the Rajput prince Sawai Jai Singh starting in 1719. Matthias Corvinus financed one of these buildings at Oradea. Another one known as the Gurkhani Zij was operated by Ali Qushji, and was the primary building project of Ulugh Beg in Samarkand. One of these on the island of Hven built by Frederick II of Denmark was known as Uraniborg, while another was founded by John Flamsteed. One of these structures at Jaipur includes the world's largest sundial. For 10 points, name these buildings like the royal one at Greenwich, used by scientists like Tycho Brahe. 
In 2007, Clive Ruggles and Ivan Ghezzi identified one of these structures built 2300 years ago at Chankillo by the Casma-Sechin culture of Peru.
observatory [accept solar or lunar or any reasonable kind of  observatories]