Ehrenfesthuis (Ehrenfest House)

Albert Einstein is perhaps the world's most recognizable scientist, mostly being associated with his work in Germany and the United States. However, from about 1920 to 1946 he was an honorary professor at Leiden University, meaning he would visit a few times a year to give guest lectures.

Since he spent a good deal of time in the city, there are many Einstein related places in Leiden, such as his sink and autograph. Most impressive of all perhaps is the house in which he stayed, the so-called Ehrenfest House.

Paul Ehrenfest was one of the most distinguished physicists of his time, together with Ludvig Lorenz, William De Sitter, Arthur Eddington, and Einstein, they were at the forefront of the theory of relativity and eventually quantum revolution. Ehrenfest was a close friend of Einstein, and insisted he stayed at his house when visiting the city. 

Einstein was not the only guest to be invited into this house, as this was the location of his famous "Colloquia Ehrenfesti," a monthly lecture series that continues to this day at the university. These lectures allowed the house to garner a large collection of autographs from scientists that have spoken at the series. Fifteen of which are from Nobel prize winners. There is even a chalkboard inside that still has text written by Einstein himself.

The house was constructed in 1914 based on a design penned by Ehrenfest's wife. It remained in their family until the 1980s, after which it was sold to Dr. W. Kuyper, who decided to preserve the house in its original state. The Museum Boerhaave is very interested in buying the house as a satellite museum. 

During the 1970s two plaques were installed at the house to commemorate Ehrenfest and his wife. 

However, this story doesn't end on a positive note. Einstein left Europe in 1933 after the Nazis came into power, permanently settling in the U.S. 

Ehrenfest fell into a deep depression, so severe that Einstein asked the University of Leiden if they could reduce his workload. That same year, he killed his 15 year old son, who suffered from down syndrome, and then himself in Amsterdam's Vondelpark.