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 Odeon of Herodes Atticus is a stone theatre structure located on the southwest slope of the Acropolis of Athens. It was built in 161 AD by the Athenian magnate Herodes Atticus in memory of his wife, Aspasia Annia Regilla. It was originally a steep-sloped theater with a three-story stone front wall and a wooden roof made of expensive cedar of Lebanon timber. It was used as a venue for music concerts with a capacity of 5,000. It lasted intact until it was destroyed and left in ruins by the Heruli in 267 AD.
The audience stands and the orchestra (stage) were restored using Pentelic marble in the 1950s. Since then it has been the main venue of the Athens Festival, which runs from May through October each year, featuring a variety of acclaimed Greek as well as International performances.