Life is full of ups and downs, and nowhere is that more true than on a roller coaster! Millions of people flock to amusement parks around the world each year to experience the thrilling and sometimes terrifying feelings that only roller coasters can provide.

If you've ever ridden a roller coaster, you've probably felt a “sinking feeling" in the pit of your stomach when the coaster plummeted down a steep hill. That feeling is caused by the sudden lack of forces pushing on your body.

The acceleration forces of the roller coaster counteract the normal sensations of gravity, and just like that, you — and all of the stuff inside you, such as your stomach — feel weightless.

So where should you go if you want to experience the wildest roller coasters in the world? If you're looking for speed, head to the United Arab Emirates. The Ferrari World Abu Dhabi amusement park is home to the Formula Rossa, which is the world's fastest roller coaster at 149.1 miles per hour!

If you're looking for a tall roller coaster with a massive drop, visit Six Flags Great Adventure in New Jersey. The Kingda Ka is the top roller coaster in the world for both height (456 feet) and drop (418 feet).

The world's longest coaster is the Steel Dragon 2000 in Nagashima Spa Land in Japan. Its total length is just over 8,133 feet — that's more than a mile and a half long!

Today, the two major types of roller coasters are wooden and steel. Wooden roller coasters are similar to traditional railroad tracks. Cars travel on tracks mounted to wooden beams.

Massive support structures are needed, so wooden coasters tend to be less flexible. Most of a wooden coaster's exciting motion is up and down.

Steel roller coasters, on the other hand, have a much greater range of motion. Steel coasters run on tracks made of long steel tubes that can be made in many shapes, including twists and corkscrews.

Steel coasters can easily tilt riders in all sorts of wild and exciting directions. Because steel coasters can be seamlessly welded together, they also tend to have a smoother ride.

Today, there are about 2,000 roller coasters operating around the world. More than 90 percent of them are steel coasters. Some of them feature new and daring designs, such as coasters that you ride lying flat so that you feel like you're flying!

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