At the bottom of the long tall blue poster, they glued little pieces of construction paper grass on the ground portion of the poster:

Then they used cotton balls and white paint to make clouds on the top portion of the poster:

Finally, they glued brown squares to represent the Tower of Babel:

One of the most obvious ways for me to tell if a craft idea was a hit is when they ask to repeat it. As soon as we were done and hung the girls' projects up, Sabrina said she wanted to make another one. So, she did (sort of):