Isaac is So Full of Energy

There is this tower at the park we were at today that you can climb to get a view from up high. It's probably about as high as two full flights of stairs. I never go up it although I have occasionally sat on the steps for a minute to rest. Isaac usually just ignores it. Today, for some reason, he decided to run up the steps to the top. Then he ran back down, then ran up again. Mind you, this was after we'd been hiking for nearly an hour. See him up at the top there?