Hellmouth
A family member worked for an airline so for several years I was able to fly standby a lot of places for free.
I went on this trip with my dad. Neither of us had ever left the country so it was pretty exciting/terrifying. We saw a performance at the Marrinsky Theatre and spent a a few days just wandering the Hermitage Museum. We also visited the Church of the Savior on Spilled Blood and a cat cafe.