Urban sprawl in reverse. Nature advancing on the city rather than the other way round. The pavement is wide so it's not creating an obstacle.

 Years ago I read a novel called 'After London' written by Richard Jefferies in 1885. The story is prototype science fiction beginning with a description of the metropolis being reclaimed by nature after some unspecified apocalypse. 

 Jefferies was a prolific author of essays on the countryside and natural history. Botanically speaking the succession he describes from city to wilderness seems very plausible. If humans disappeared it wouldn't take long...