At the foot of Telegraph Hill, San Francisco

You might think the apartment building on the left and its pedestrians are victims of erosion. But the nearby wall of rock has been that way since the Gold Rush days.

Starting in 1849, ships came to San Francisco (known then as Yerba Buena) from around the world bringing mining equipment and people who wanted to get rich by filling their pockets with gold nuggets.

Since the town was a small fishing village, there was nothing for the ships to carry away. Some were anchored offshore and used as housing. When more than a hundred blocked the port, some were burned. 

Some of the ships managed to sail on to other ports by replacing their cargo with ballast in the form of rocks created by dynamiting Telegraph Hill, leaving it with a flat side. 

So it would seem that apartment building and its pedestrians are the victims of building too close to a known hazard. 

Not to worry: management has "solved" the problem but installing a sign.