Mushrooms look soft, but are sometimes able to exert surprising force. A new tarmac surface was laid on this pavement in 2010. Just a few weeks later, a clump of small glistening inkcaps forced their way to the surface, pushing a patch of the tarmac aside.
Since then, there has been a fresh patch of these mushrooms every year at about the same time. As they emerge, the hole in the tarmac is being enlarged bit by bit.