The Rundetårn (Round Tower) is a 17th-century tower located in central Copenhagen. One of the many architectural projects of Christian IV, it was built as an astronomical observatory. It is most noted for its 7.5-turn helical corridor leading to the top, and for the expansive views it affords over Copenhagen.
The tower is part of the Trinitatis Complex which also provided the scholars of the time with a university chapel, the Trinitatis Church, and an academic library which was the first purpose-built facilities of the Copenhagen University Library which had been founded in 1482.
Today the Round Tower serves as an observation tower for expansive views of Copenhagen, a public astronomical observatory and a historical monument. In the same time the Library Hall, located above the church and only accessible along the tower's ramp, is an active cultural venue with both exhibitions and a busy concert schedule.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.