The Oval Room in the Teylers Museum was the first part of the museum (though it was not called a museum yet) that was opened in 1784. It could be entered through the garden of the fundatiehuis, the former home of Pieter Teyler van der Hulst. The building has an oval shape built around its centerpiece, a mineralogical cabinet. The Oval Room consists of two floors; the ground floor with its display cabinets and a gallery of books that connects to the Teylers Library. On top of the room, on the roof, the astronomical observatory used to be a landmark that could be seen for miles along the river Spaarne. The gallery and observatory are longer accessible to the public, though the gallery can be seen from the ground floor.