It's amazing what creative people with lots and lots of free time have done with water barrels... I remember once years ago a guy decided to blockade the entire city of Britain with them.
No matter which direction you tried to leave the city from, there would be rows and rows of water barrels blocking your exit. It was like that on every single entrance and exit from Britain. He must have spent the entire day doing nothing but filling water barrels. It was hilarious watching people's extremely confused reactions when they would suddenly run into these walls of barrels. Some of the exits had so many that you couldn't see the end of them anywhere on your screen.
I miss that kind of genius but completely insane level of UO creativity.