Walking tour Leiden Marathon 21 km

Leiden University (abbreviated as LEI; Dutch: Universiteit Leiden) is a public research university in Leiden, Netherlands. It was founded as a Protestant university in 1575 by William, Prince of Orange, as a reward to the city of Leiden for its defence against Spanish attacks during the Eighty Years' War.

The Hortus botanicus of Leiden is the oldest botanical garden of the Netherlands, and one of the oldest in the world. It is located in the southwestern part of the historical centre of the city, between the Academy building and the old Leiden Observatory building.

The Bibliotheca Thysiana was erected in 1655 to house the book collection of the lawyer Johannes Thysius (1621–1653). Upon his early death, he left a legacy of 20,000 guilders for the building of a public library ("tot publycque dienst der studie") with a custodian's dwelling. Designed by the architect Arent van ‘s-Gravensande, the building follows the Dutch Classical style and is regarded as one of the jewels of Dutch 17th-century architecture.

The International Institute of Air and Space Law (IIASL) is a leading research and teaching institution. It specialises in legal and policy issues for aviation and space activities. It forms part of the Leiden Law School at Leiden University.The institute co-operates with many sister institutions and maintains contact with national and international organisations throughout the world.

The Heilige Lodewijkkerk, also called the St. Louis Church, is a Roman Catholic church at the Steenschuur in Leiden.

St. Joseph Church is the largest Roman Catholic parish church still in use in Leiden in the diocese of Rotterdam. It is also called the Herensingelkerk, because it is situated at the street called Herensingel. The church is a national heritage site and one of the tallest buildings in the centre of Leiden.

Leiden Lammenschans is a railway station in Leiden, Netherlands. The station, designed by Koen van der Gaast, was opened on 18 May 1961. It is served by trains running between Leiden Centraal and Utrecht Centraal, and by RijnGouweLijn trains running between Leiden Centraal and Gouda at peak hours.Leiden Lammenschans was named after the nearby fortification Schans Lammen, the encampment of the Spanish troops during the Siege of Leiden in 1573 and 1574.

De Valk is a tower mill and museum in Leiden, Netherlands.The current tower mill is the third mill built at this location. In 1611 the post mill "De Valck" was built, and in 1667 it was replaced by a wooden post mill. In 1743 a higher tower mill was built. De Valk originally was equipped with six mill stones.

The Rijksmuseum van Natuurlijke Historie (National Museum of Natural History) was a museum on the Rapenburg in Leiden, the Netherlands. It was founded in 1820 by Royal Decree from a merger of several existing collections. This happened on the initiative of Coenraad Jacob Temminck, who saw the museum primarily as a research institute for the University of Leiden.

The Rijksmuseum van Oudheden (English: National Museum of Antiquities) is the national archaeological museum of the Netherlands, located in Leiden. It grew out of the collection of Leiden University and still closely co-operates with its Faculty of Archaeology. The museum calls itself "the national centre for archaeology" and focuses on ancient Egypt, the ancient Near East, the classical world of Greece, Etruria and Rome and the early (prehistoric, Roman and Medieval) Netherlands.