In 1865 it seems that some people in Amsterdam noticed they were polluting the river Elz with human waste. Hauling odiferous material out of the castle on wagons was unpopular also.
If you want the concrete you pour to have maximum strength and durability, you must make sure it is cured properly. You can do this by maintaining the right moisture content in the concrete during the first seven days after it is placed (three days for high early-strength concrete).