Animations, like transitions, can alter page elements over time. Animations are more powerful and more complex in many ways. You need to declare an animation with a special syntax before you can use it, which allows you to specify values for multiple properties at different percentages of the animations completion ("keyframes"). Then when you do use it, there are lots of values you can set as to how you want it to behave. We'll cover all that as we build a fun little animated scene.