Since 1414, the Saint Cecilia Monastery, which became the property of the city by the Reformation, stood here. In 1596, it was transformed as a home for the city's most repellant plague sufferers... the city's first Pesthuis.

Today, it is a serene park, but it marks the site of what was once one of the deadliest national disasters in modern Dutch history

The Orphanage, formerly known as the Holy Spirit or Poor Orphans and Children’s Home, is one of the largest monuments in Leiden. Operating for nearly 400 years, orphaned children stayed in the building on Hooglandse Kerkgracht, with as many as 579 children at its peak.

Pieterskerk Leiden has a surprisingly macabre and dramatic past, featuring a catastrophic 16th-century tower collapse, thousands of hidden graves under your feet, and unsettling WWII tales.

The Gravensteen in Leiden is one of the city's oldest buildings and holds a notoriously dark history. Originally built as a private refuge tower for the Counts of Holland, it transitioned into a medieval prison, torture chamber, and execution site, leaving behind a chilling legacy.

Galgewater translates literally to "Gallows Water". Dating back to the Middle Ages, this canal in Leiden's historic center earned its grim name because the city’s execution grounds and public gallows were stationed along its banks, serving as a dark warning to criminals.

The name "Morspoort" literally translates to "Marsh Gate". It gets its name from "De Morsch," a swampy, desolate marshland that sat just outside the city walls—the perfect backdrop for medieval dread and executions.

Rijksmuseum Boerhaave, named after the renowned scientist Herman Boerhaave, is a fascinating museum in Leiden that showcases scientific and medical objects dating back to the 16th century. Housed in a historic 15th-century convent, which was once Northern Europe's first academic hospital, there is a history of truly disturbing medical mishaps and autopsies in the prominently displayed medical theatre.

On the Rapenburg canal, Leiden University opened one of Europe's first anatomical theatres in 1594. During winters, professors of anatomy held public dissections of cadavers to a fee-paying audience of students and surgeons, but also curious members of the public. The bodies dissected were not just those who died of natural causes. Surgical instruments on display were also used to dissect the bodies of executed criminals, and those dissections attracted regular crowds of curious spectators

The World's Deadliest Poisoner In the 19th century, Leiden harboured a serial killer whose crimes went undetected for years precisely because she seemed so kind. Maria Swanenburg, better known as "Goeie Mie" (Good Mie), was responsible for poisoning nearly 102 people, 90 of whom died. Her crimes went undetected for years because she poisoned her victims' food with arsenic powder, an undetectable method at the time.