Once upon a time, this world must have been a beautiful place. Houses were made out of wood and/or adobe bricks, streets were unpaved and only churches, bridges and castles were built in stone.
Unfortunately, mankind discovered the use of reinforced concrete and that has changed everything. Nowadays, concrete is omnipresent and it seems to me, that construction will not stop until even the remotest place has received a little attention from the concrete truck. Like a busy bee, it is everywhere and it never rests.
Traveling and visiting volcanoes made me realize that they play an important part in the conquest of the world by concrete. They provide the sand and gravel, which, I guess, help to make excellent concrete.