1. Zip World Velocity

Branded the longest zip line in all of Europe, Zip World's Velocity wire in Bethesda, Wales is a must-see for any true adventurer. Stretched across the edge of the breathtaking Snowdonia National Park, Velocity includes two zip lines, nicknamed the Little Zipper and the Big Zipper. The Little Zipper is much less daunting and is used to prepare riders for the thrills to come, while the Big Zipper carries riders almost 1,600 yards over mountains and water before dropping them safely to the ground on the opposite side of Penrhyn Quarry.

2. El Monstruo

Located at Toro Verde Park in Orocovis, Puerto Rico, El Monstruo, or "The Monster," holds the official Guinness World Record for being the longest zip line in the world. Approximately the length of 28 football fields, this monstrous 8,3000-foot (2,529.84m) cable takes riders on a fast-paced journey through the Puerto Rican jungle, zipping down mountain sides and over rivers. The Monster's 95 mph speeds make this line the perfect zipping experience for any serious thrill-seeker.

3. Cloudscraper

Towering 1,200 feet (365.76 m) over the roaring Arkansas River, the Cloudscraper holds the title of highest zip line in North America. This thrilling, death-defying wire located in Canon City, Colo., carries adventure-seekers alongside the Royal Gorge Bridge and over the breathtaking canyon below. At a length of 2,400 feet (731.52m), riders can fly through the air at breakneck speeds, making Cloudscraper the perfect fit for anyone searching for the ultimate adrenaline rush.

4. Zipflyer

Nepal's Highgrounds Adventure Park is home to the steepest zip line in the world. Located in Pokhara amidst the breathtaking, snow-capped Himalayas, Zipflyer is truly a once-in-a-lifetime experience for any adventurous soul. With a 2,000-foot (609.6m)  vertical drop, Zipflyer is perfect for big-time thrill-seekers. Reaching speeds up to 80 mph, this 6,000-foot (1,828.8m) ride is sure to seem daunting to even the bravest of adrenaline junkies.

5. Mega Zips

Located 17 miles beneath Louisville, Ky., Mega Cavern adventure park is home to the world's only fully underground zip line course. Complete with six different zip lines, including one dual-racing wire that sends riders barreling into the darkness below, Mega Zips is perfect for anyone looking for a unique zip lining experience. With educational tours and additional ropes courses and activities, Mega Cavern has something to offer everyone.

According to travelchannel.com. Source of photo: internet