The Citadel of Calais was built between 1560 and 1571 on the site of a former medieval castle which was built in 1229 by Philippe de Hureprel. Its purpose of its construction was to fend off would-be invaders, but it wasn't long until the city was successfully invaded by Archduke Albert of Austria on 24 April 1596. Both Louis XIII and Cardinal Richelieu at one time considered expanding the citadel and Calais into a great walled city for military harbour purposes but the proposals came to nothing.
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.