Here's one of my favorite sunset pictures, the sun setting over the edge of the Australian outback, framed by a bottle tree. Bottle trees are named after the fact that the trunk looks like a bottle, and that it holds a lot of water. The insides of the trunk are very fibrous instead of being dense like most hardwood trees we know. Having all of these gaps inside of the trunk allows the tree to retain a lot of water, a fact exploited by the settlers and indigenous peoples of the drought stricken Australia.
It can get 18-20 meters in height and 2 meters in width (60 ft high and 6 ft across). It is also called Kurrajong, which is derived from the word 'fishing line' in one of the aboriginal dialects. The fibrous inner part of the bottle tree was often used to make twine products, such as fishing lines.
Here's a picture of a bottle tree in the day time: