Stadel Museum in Frankfurt, Germany has opened a €52m underground extension to house its contemporary art collection.
The underground exhibition space, called the Garden Halls is the first extension to the museum since it was built in 1878.
The underground halls, situated beneath the Stadel garden adjoining the early twentieth-century Garden Wing, have been designed by the German architects schneider+schumacher.
Stadel Museum director Max Hollein said: "Thanks to the unparalleled dedication of many, with its new building and the substantial expansion of its contemporary art collection, the Stadel has made yet another quantum leap in its history of nearly 200 years."
The extension is accessed by following a central axis from the main entrance facing the river Main.
The floodlit halls provide 3,000m² of additional exhibition space, doubling the area available for the presentation of the Stadel's holdings.
The Garden Halls' interior features a curved ceiling resting on twelve columns.
Reaching 8m in height, the new halls are supplied with light through 195 round skylights measuring 1.5m to 2.5m in diameter.
The skylights are equipped with a solar control system which prevents the penetration of direct sunlight, as well as darkening mechanisms making it possible to shut out daylight altogether.
Additional rings of warm and cold white LED lamps guarantee the even lighting of the paintings and other exhibition objects and permit the individual control of each of the 195 skylights.
A modular wall system represents the prerequisite for completely flexible exhibition design within the Garden Halls.
Image: The new halls are lit by 195 skylights. Photo: Stadel Museum.