The world is full of interesting, breathtakingly beautiful places to visit. If you're looking to get off the couch and go on an adventure, there's certainly no shortage of options, from whitewater rafting to snow skiing to rock climbing.

But if you're looking for a true challenge with unrivaled sights, you need a day hike. Sure, it requires being in good shape and able to cover a couple dozen miles in most instances, but the effort will be worth it. Here are five day hikes worth the haul, but there's a disclaimer: they all include some level of danger, be it from exhaustion or the elements.

Follow us on Facebook and Twitter to read them first!

Mt. Whitney, California

Climbing mountains is often romanticized and with good reason. It's a challenge, requires a number of skill sets most of the time and the views and experience are incomparable. So when you have a chance to hike a mountain like Mt. Whitney, armed with a guide and all the endurance you can muster (it's a 22 mile round trip hike), you should accept the challenge when you're ready. It's roundly hailed as one of the most rewarding hikes in America.

Volcan Pacaya, Guatemala

In average shape, but want a once-in-a-lifetime experience? Climb an active volcano. Sounds like a suicide mission, but if you get the right guide, you likely won't be steered into harm's way. Still, you accept some risk when you venture up Pacaya. Reaching the top of the crater takes anywhere from 2.5 to 3 hours, and less time on the way back down. The final stretch to the top is the toughest, as climbing through volcanic ash and rocks is akin to climbing an angled beach -- you'll feel the burn. But the summit is worth it, with expansive views for miles and a rare look at an active volcanic crater.

Grand Canyon Rim-to-Rim, Arizona

The Grand Canyon is considered a must-see experience for many Americans, and the views alone during a car trip the national landmark are worth the visitors' time. But a richer and more complete experience can be had by trekking on this march, which ranges from 21-to-24 miles, depending on the trail taken. But it's not for the faint of heart. As DayHiker.com warns: the park service and all printed guides heavily discourage the hike -- too many people that try find themselves in trouble and need to be evacuated.

Salkanty Trek, Peru

Machu Picchu is among the greatest hiking destinations in the world. It offers a chilling connection to the past and some of the most breathtaking views on the planet. But getting to it comes at a price, one your legs will pay dearly for. There are a few different hikes to the top, but the Salkantay Trek takes hikers over a 15,000 foot pass and through rural valleys still using ancient farming techniques, according to Gadling.com. Before you even start hiking, you'll have to take a few rides across mountain ledges that can be more intense than the hike itself. You may test your heart rate, but you won't be able to say it was boring.

London

Perhaps the wild isn't your thing, and an urban setting keeps you in your comfort zone. Dayhiker.com again has a solution: a march through the west-end that starts in the Theater District and includes stops at all of the Thames bridges, the Globe Theater and all the major parks. The hike can be as extreme or as limited as one sees fit. But it's entirely possible to cover 12+ miles along the way, with time set aside for stops at each sight.

Popular Stories On ThePostGame:
-- 12 Marathons For 2012
-- College Basketball's Dad-Son Coach-Player Duos
-- Rift Over Tim Tebow Custom 'Jesus' Jerseys
-- World's Best Backpacking Trails? Try Colorado

1939 Dodge Still Runs -- As A Grill