The university has no central campus; its buildings are spread over the city. Some buildings, like the Gravensteen, are very old, while Van Steenis, Lipsius and Gorlaeus are much more modern. Among the institutions affiliated with the university are The
KITLV or Royal Netherlands Institute of Southeast Asian and Caribbean Studies (founded in 1851), the Leiden Observatory 1633; the Natural History Museum, with a very complete anatomical cabinet; the
Rijksmuseum van Oudheden (National Museum of Antiquities), with especially valuable
Egyptian and Indian departments; a museum of Dutch antiquities from the earliest times; and three ethnographical museums, of which the nucleus was
Philipp Franz von Siebold's Japanese collections. The
anatomical and
pathological laboratories of the university are modern, and the museums of geology and
mineralogy have been restored. The
Hortus Botanicus (botanical garden) is the oldest
botanical garden in the Netherlands and one of the oldest in the world. Plants from all over the world have been carefully cultivated here by experts for more than four centuries. The Clusius garden (a reconstruction), the 18th-century Orangery with its monumental tub plants, the rare collection of historical trees hundreds of years old, the Japanese
Siebold Memorial Museum symbolising the historical link between East and West, the tropical greenhouses with their world-class plant collections, and the central square and Conservatory exhibiting exotic plants from South Africa and southern Europe.
Zweetkamertje The "Sweat Room" () is a small chamber in the university's Academy Building, traditionally used by doctoral candidates awaiting the results of their PhD defenses. The room is renowned for its walls covered with the signatures of graduates, including notable figures such as
Winston Churchill,
Nelson Mandela, and members of the Dutch royal family. Originally serving as a meeting room for university curators, the Zweetkamertje became associated with doctoral examinations in the 18th century. Candidates would wait in this room before defending their dissertations, often experiencing considerable anxiety, hence the name. Over time, it became customary for successful candidates to inscribe their names on the walls as a rite of passage. While the tradition is primarily associated with doctoral candidates, all master's students are also permitted to sign the walls upon graduation, meaning that some individuals have added their names multiple times over the course of their academic careers. The tradition of signing the Zweetkamertje walls is a cherished aspect of Leiden University's heritage. The room features thousands of signatures, including those of honorary doctorate recipients. In 2014, a crowdfunding campaign successfully raised funds to restore the room's deteriorating plaster, ensuring the preservation of this unique historical record.
Campus The Hague In 1998, the university has expanded to The Hague which has become home to
Campus The Hague, with six of the seven faculties represented and exclusive home to the Faculty of Governance and Global Affairs, International Studies and
Leiden University College The Hague, a liberal arts and sciences college. Here, the university offers academic courses in the fields of law, political science, public administration and medicine. It occupied a number of buildings in the centre of the city, including a college building at
Lange Voorhout, before moving into the new 'Wijnhaven' building on Turfmarkt in 2016. The Faculty of Governance and Global Affairs was established in 2011, together with the University College, and one of the largest programmes of the Faculty of Humanities, International Studies. Since 2017
Leiden University Medical Center also has a branch at Campus The Hague. ==Organisation==