MongoDB User Group Munich is a place for developers to learn more about MongoDB, an open source, document-oriented, nosql database.
The user group discusses stories by MongoDB users and their benefits. Also presents current developments of MongoDB.
More information is available on their meetup page: https://www.meetup.com/MUGMunich/
If you want to learn more about MongoDB in detail, please have a look at the MongoDB University, which offers free courses for developers and administrators, incl. certifications: https://university.mongodb.com/
If you want to get hands-on experience, you can spin up a free cluster in the fully managed service MongoDB Atlas (https://atlas.mongodb.com). Getting Started guides help you to take the first steps and load example data: https://docs.atlas.mongodb.com/getting-started/.
Did you have the chance to work with the latest features, like data visualization and data lake access? Take a tutorial on MongoDB Charts (https://docs.mongodb.com/charts/saas/) or learn how to query a data lake via MongoDB Query Language (https://docs.atlas.mongodb.com/data-lake/).