Fun fact from Germany! These giant Christmas markets actually double as parking lots outside of holiday seasons! Everything is temporarily built on top of a giant parking lot!
Furthermore these tend to be close to both major hubs (Think like a central train station!) and some other event areas that DO need the parking (like a football stadium!). That way, while the holiday markets (plural, several a year) are off, the space can also be used as parking space for sports events hosted in the adjacent stadium!
Just some amazing German efficiency for you. Oh also they frequently get used as skateparks.