Roolku set up a challenge for more non-micro urban caches, after seeing reports of a giant cache container in the middle of a German roundabout being adopted as a piece of modern art by the local council. This is my response. It is in the shape of a 35mm film container, but is 25 Litres (ie 5 gallons) capacity. The place is not the most exciting, but affords some views over the rooftops to the city centre.
There is a big logbook, and a separate container for TBs and geocoins so they don't get lost in the vastness of this cache.
The lid top of the drum is held in place by a metal ring. Place the lid on the drum first, and then place the metal ring over the edge of the lid and the top of the drum. Please be very careful that the ring covers both the lid, and the top of the drum to ensure there is a watertight seal.