The Margravial Opera House in Bayreuth, the German town that hosts the annual Wagner festival, joins the list of sites classed by UN cultural body UNESCO as world heritage, the organisation said on Saturday.
The World Heritage Committee, which is meeting in Saint Petersburg, called the opera house "a unique monument of European baroque music festival culture", UNESCO's German Commission said in a statement.
Stepping into the opera house, one of the few of its kind still existing in Europe, is like going back in time to the late baroque.
It lies just over a kilometre south of Richard Wagner's Festival House where the composer's operas enthrall music lovers from all over the world every summer.
The opera house which owes its splendid interior to Italian artist Giuseppe Galli da Bibiena has a ballroom typical of the Absolutist society at the time with wooden dressing rooms, unique streaked marble and painted decoration.
"Even the acoustic sounds like it did 270 years ago," according to UNESCO.
The opera becomes the 37th site in Germany named onto UNESCO's prestigious list, making the country one of the most prolific in World Heritage sites.