From researching plastic pollution to caring for injured wildlife, volunteers play a crucial role in conservation. But much of the valuable knowledge they gather remains unused.

We all know smoking is bad for our health. But we might not have known that the cigarette filters that litter our streets also impact the environment. Esther Kentin is a lecturer at Leiden Law School. She is raising awareness of the University’s cigarette butt problem.

Every Sunday you can help fish plastic and other floating garbage out of the Leiden canals. You can use your own canoe or loan one from Plastic Spotter and join the garbage-fishing fleet. Annetje Ottow, President of Leiden University, was one of the crew on Sunday 4 July.

In the Port of Rotterdam, tiny industrial pellets leak into the environment, causing a form of pollution that’s hard to trace but highly persistent. Three students of the LDE Sustainability Honours Programme took on the challenge to identify sources of this pollution.

Lecture, Studium Generale

The university is launching a campaign to focus extra attention on our smoke-free university locations. The University is using aptly named cigarette barrels to try to show clearly just how many cigarette filters are being saved from the environment. How harmful are these cigarette filters to the e…

Nanoplastics can accumulate in developing hearts, according to a study by biologist Meiru Wang from Leiden University. Her research on chicken embryos sheds new light on how these tiny plastic particles pose a threat to our health.

Arts and leisure, Arts and leisure

Purple clothing and a pride flag flying from all University buildings: Leiden University is once again taking part in Purple Friday. How do people experience this day? We asked some employees and students of the Faculty of Humanities.

Some thirty Leiden students balanced on SUP boards for the Supping for Sustainability Lustrum activity. Together with alumnus Merijn Tinga, better known as the Plastic Soup Surfer, they paddled their boards through the Leiden canals and waterways, fishing plastic waste out of the water.

Gain the knowledge and skills you need to make an impact on sustainability issues.

Life returned to something resembling normal after Covid but other crises soon took its place. These great challenges are also being felt at the University and our researchers are working on solutions. The nitrogen crisis, problems with young people’s services and an increasingly urgent climate crisis:…

Facility

In recent months, the university has been running the 'Smoke-free university' campaign because of the large number of cigarette waste on and around the faculties. As part of this campaign, gatherings were held in June, September and October to draw extra attention to this waste problem.

Since 24 March, the Kamerlingh Onnes Building of the Faculty of Law has been full of hundreds of colourful jellyfish. But behind that enchanting sight is a serious message: the exhibition symbolises the loss of biodiversity in the oceans due to climate change.

Amid the many traditions of Leiden’s 3 October Festival, a relative newcomer is beginning to take hold: the Science Market. At market stalls, the people of Leiden could explore or even participate in Leiden’s research – performing an ‘operation’ in the street, for example.

What better way is there for an alderman to find out where best to put his efforts than to pay a working visit to the university? Hilbert Bredemeijer, Alderman in The Hague for Education, Sport and the Outdoor Space, paid a visit to Campus The Hague on Wednesday 6 October 2021.

Buurtlab 070 is a new Leiden University project in which residents, researchers and students from The Hague work together on climate, sustainability and biodiversity solutions. What do they expect of the lab?

Are you curious about how the human skeleton works? Discover this and more on 3 October in Leiden and on 4 October in The Hague.

What is the relationship between humans and nature like? And how can we use it to tackle climate problems? In the Master Honours Class ‘Planet in Peril’, students approach climate issues from the perspective of the humanities. ‘Things are not always as one-sided as they seem.’

Students who also want to develop their artistic talents can take a year-long art class – Practicum Artium – at the Royal Academy of Art in The Hague. ‘I can express my creativity and am learning to approach subjects in a visual way.’

Taking a Bachelor’s in Security Studies while starting and running two businesses: student Mohamed Sulaiman never stops. But he wouldn’t have it any other way. PLNT The Hague entrepreneurs’ hub is a source of help and inspiration.

What does the University mean for The Hague? And what are researchers and students learning from the city and its residents? The Hague city councillors visited Campus The Hague on 27 September and spoke to administrators and researchers. ‘From Schilderswijk to Benoordenhout: we are a university for…

The course Designing Your Life helps students navigate their career pathways. As it turns out, these pathways are full of twists and turns and - as with many journeys - you only make progress once you gather the courage to take the first step.

Lecture, Studium Generale

Exhibition

450 jaar

Arts and culture

Annetje Ottow is stepping down as President of Leiden University’s Executive Board on 1 September 2025 after almost five years in the role. She looks back at the highs and lows – and ahead to what’s next.

How has evolution shaped our curiosity? And how does that curiosity ensure that we now have the technological ability to discover whether we are alone in the universe? This was all covered during the celebration of Leiden University’s 449th Dies Natalis.

Bram Geurds (20) is fascinated by politics. When he was 12, a political debate on TV caught his attention. And he decided he wanted to be mayor one day. Unsurprisingly, Bram is studying political science and is politically active. It might seem like he’s on course to become a professional politician.…

Never before has so much research been carried out on the therapeutic effect of psychedelic drugs. Researchers at the LIBC Public Day are happy about the effect the drugs can have on depression, anxiety and PTSS, but at the same time they have some doubts. ‘The hype is bound to crash before long.’