https://www.youtube.com/watch?v=oOop5qYniJw
Skating the Rideau Canal is on my bucket list. I didn't realize that they maintained the ice so carefully.
If you look for "biggest ice rink" on a search engine, a lot of people and places claim they have it.
E.g.,
https://www.npr.org/2018/01/02/575028113/moscow-boasts-that-it-has-the-worlds-biggest-ice-rink
https://www.youtube.com/watch?v=zl17yGW8B-w
https://www.reddeeradvocate.com/uncategorized/the-biggest-ice-rink-in-the-world/
etc.
...