For school, we have made an animation in a smaller group. Our group was called Studio Sloth. We were a group of 6 people, where each of us had one or more (slightly) different roles. I was the concept artist and art director, both of those roles done together with another girl, and I was also the background designer.
Our animation is about an explorer, Pedro, who is in search of a golden hourglass. He finds the hourglass in an ancient temple, which - unbeknownst to him - is surrounded by a civilization of sloths. The hourglass turns out to be a magic artifact, which can control the speed of the sloths. Pedro tries to escape from the sloths with the hourglass, but runs into some resistance.
Some early sketches of plants, a tree and the relief that can be found within the temple:
Some sketches of different parts of a town that we were originally going to have around the temple. We ended up scrapping this idea, because we felt it didn't add anything to the story.
Some concept art for the jungle and temple:

Basic Colour Script:
Original background for a vertical slice:
After we made the vertical slice, we came to the conclusion that the style of the background didn't really fit with the style of the characters. I then made some new sketches, to come up with a new style, that fit better:

Some of the final backgrounds:
The finished animation: