It now extends across two walls, but depending on your children's interest and involvement, you may want to go further. Finding inspiring color pictures wasn't as hard as we expected. After going to thrift stores and a few yard sales and purchasing used picture Bibles, we had enough pictures to begin. We keep these books on a separate shelf in our 'library' which the children know is just for cutting out the pictures. Building the timeline could be woven into your child's Bible History lesson.
Children can search through the picture books and find the character they studied about.
Or make it a family project to put one up each day. Or perhaps offer as 'extra credit' for those who research and make the next timeline picture. Children may want to add a color backing before mounting on the wall. Plastic laminating will preserve the timeline pictures best, though sheets of clear contact paper work also. Another idea for making Bible History come alive is presenting plays on the characters in the Bible for other family members.