Thank you for your corrections! "Pedestrian zone" is a literal translation from Russian. We use this term to call those streets where traffic has been banned, and where people walk not only along the sidewalks, but also along the road.

"Today I went to the downtown of the city and were surprised how strongly it changed." => Today I went downtown and was surprised by how strongly it changed. (Strongly is a weird word to use in this context, imo. You can try "heavily." "Lots of cafes, restaurants and pubs settled around the pedestrian zone." "Settled" is a strange word here, as well but I think you can get away with that as long as you say "were settled." And I'm not sure what pedestrian zone is. Sidewalks? "The World Cup has just started, and Saint-Petersburg is also one the cities which host football teams all over the world." => The World Cup has just started, and Saint-Petersburg was one of the cities hosting international football teams. "Unluckirly, I'm not a football fan. However, I'm pleased that people have such a great sports festival." => Unfortunately, I'm not a football fan. Nonetheless, I'm pleased that such a great sports festival exists. Well, you spelled "unluckily" wrong. :) But I think a better word is "unfortunately." "Nonetheless" would also be better than "however." Good luck! Great job! *yikes, it won't let me add spaces in between my paragraphs...let me know if this is difficult to read*