Ask HN: How can I professionally make the most of moving to a big city?

Hi HN. I recently moved across the pond from a smallish town in America to Europe (Berlin fwiw). One of the draws for me here (among many others) is the opportunity to further myself professionally. Where I have been living, the tech space is tiny relatively speaking. That said, what are some of the best parts of living in a large city for you? What's worth (or a waste of) your time? What has helped you grow the most or just been interesting? Looking forward to hearing about your experiences.