writes: National Geographic takes a high-level look at the physics behind waterslides. A lot of science goes into providing a safe 60 mph trip down slides like Walt Disney World's 10-story Summit Plummet. "Safety is our number one concern," explains Rick Hunter of ProSlide Technology ("Engineered Exhilaration"). "We're thinking about things like, 'Are you going to stay on the fiberglass tube?'. It's really easy to do a computer model and look at curves and drops and forecast rider position and speed." If you're making your waterslide bucket list, BuzzFeed's got pics of 18 favorites from around the world. Any others worth checking out before summer's over?