The Pergamon Altar, one of the most famous museum exhibits in Berlin, has been unavailable for viewing in recent years, disappointing many visitors to the city.

Now, local officials say the entire building housing the altar with its many antiquities must close for at least four years for extensive renovation work.

The Pergamon Museum is now not scheduled to fully reopen in its entirety until 2037, after an estimated cost of 1.5 billion euros ($1.6 billion) in restoration work.

A section of the museum housing the world-famous Pergamon Altar, an ornately carved ancient Greek stone temple that has been a huge attraction in Berlin for more than a century had already largely been closed off since 2013.

But the Prussian Cultural Heritage Foundation and the Federal Office for Building and Regional Planning in Berlin say the Pergamon Museum in Berlin, one of Germany’s most popular museums will have to be completely closed until 2027 to allow for renovation work.

Erected between 1910 and 1930, the building is a dominant part of the so-called Museum Island in the heart of the capital. The ensemble of museums, consisting of five historic museum buildings, has been classified as a World Heritage Site by UNESCO since 1999 because of its special significance.

The Pergamon, which includes the Collection of Classical Antiquities, the Museum of the Ancient Near East and the Museum of Islamic Art, attracts over 1 million visitors every year.

Beset by construction works for a decade, the museum had initially wanted to remain accessible by splitting its extensive construction plans into two phases, but these plans have now been changed.

Section A of the museum, which has been closed since 2013, with the north wing and the famous Pergamon Altar in the central section, should be accessible again in 2027. The second section B closes on Oct. 23.