Florida Keys, FL
Water, Water Everywhere
The 100-mile highway is unquestionably one of the most spectacular (and unique) drives in the U.S. Nowhere else can you literally drive out to sea.
Your kids will be wowed -- at least temporarily -- by the road itself, which seems to float on water. Tell them to look left. That's the Atlantic. Look right, that's the Gulf of Mexico.
The highway also crosses 43 bridges (have them keep count to pass the time). Each span is fairly high, so the littlest ones can actually see emerald green lagoons, olive-green mangroves, and maybe even some wildlife down below.
Once they've lost interest, start making those pit stops for snorkeling, bird watching, and blowing off steam on the nearest island. Here are the most popular spots: