Älvsborg, also Elfsborg Fortress, is a sea fortress situated on the mouth of the Göta Älv river. It served to protect Sweden's access to the Atlantic Ocean and the nearby settlement of today's Gothenburg and its four predecessors. The fortress was relocated in the 17th century, this New Älvsborg Fortress is still maintained. Of the Old Älvsborg Fortress, only few ruins are visible today in the vicinity of the Carnegie-pier. The new fortress was founded in 1621 by Gustavus Adolphus of Sweden.
In 1643, a settlement in New Sweden, North America, was named Fort Nya Elfsborg, after the Swedish fortress. This settlement was however abandoned in 1655.
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.