About Leiden European City of Science

The European City of Science hosts the Science in the City Festival which is an important feature of every EuroScience Open Forum dedicated to people of all ages who are curious about science and technology. It is one of the largest public engagements in science and technology events in Europe. The city of Leiden was awarded with the title of European City of Science for the 2022 edition. 

Why Leiden?

Many cities claim to be cities of science, but Leiden truly is one. The city and the University of Leiden has always been a place where talent, expertise, and freethinkers have gathered to bring about the latest innovations and cutting-edge technologies century after century. The values of freedom and open debate are reflected in the mottos of both the university, “Praesidium Liberatis”, Bastion of Freedom; and the city, “Haec Liberatis Ergo”, for the sake of liberty. It is in spirit of freedom, curiosity and openness that make Leiden the logical choice for the title of European City of Science to showcase science on an international scale during ESOF2022 and beyond with the Leiden2022 festival.


Leiden2022 is a special edition of the Science in the City Festival. It will be a true year of science where every day of 2022 will highlight something new. The city’s partners have come together to organize a year-long, immersive, and city-wide exploration of all thing’s science, technology and art that offer something for everyone— young, old, expert or novice.

For 365 days and across the 101 neighborhoods in and around Leiden, the entire city will come alive with interactive activities, workshops, excursions, exhibitions, and events designed to help connect science with society, the general public and all those with curious minds. From the latest discoveries from the cosmos to exploring the biodiversity of a local park and everything in between, Leiden2022 has a theme that will captivate and challenge the inquisitive nature within us all.

"Excellence in science often refers to scores, publications, and awards. But what I will also like to see this year is people excelling in connecting science and society. Science has never been more relevant and is more accessible than ever.”

Who knows?

Who Knows is the overarching theme of Leiden2022 where 22 big, topical yet timeless questions feature prominently in the programme. This ambiguous phrase of Who Knows evokes the inquisitive spirit of our times as we yearn and seek knowledge, while also pondering the important existential questions that accompany scientific breakthroughs. Who has access to science and reliable information? Who legitimizes science and its applications? What is true and what is socially acceptable? What is the future of science? The answer to all these questions is: who knows! Whether you read it with a question mark, an exclamation mark, colon or full stop, Who Knows is a provocative expression meant to challenge what we think we know, the fraught relationship between science and citizens, and the future of this important discipline.

So, what does Who Knows mean to you?

“Trust your curiosity and let it be your guide, and you can look forward to some extraordinary experiences in Leiden this year.”

Intrigued by the possibilities of Leiden2022? Are you ready to be tested and amazed? The Leiden2022 festival is waiting for you!