MongoDB.local London is an upcoming event where users can learn about the latest developments in MongoDB, including its security features, data lake service, and machine learning capabilities. The event will feature talks from various speakers, including new members of the MongoDB family, customer talks, and sponsor talks. There will also be a series of presentations on topics such as Stitch, Realm Mobile, and backup strategies. Additionally, attendees can enjoy food, drinks, and games, including slot car racing and Mario Kart. The event is designed to cater to all types of users, with a Women & Trans coders lounge providing a safe space for underrepresented groups in the engineering community.