Our world has so many spectacular places to explore, and with transport links and travel apps

constantly improving, the most secluded corners of the earth are now closer than ever. However,

there are some places that are too dangerous, protected, or special to step foot on. Whether

it's a network of abandoned mines, haunted islands, or top secret military facilities,

here are some of the most fascinating places you're not allowed to visit.

And the people who did anyway.

The village of Box in England is nestled within a picture-perfect-looking parish.

But this place isn't as flawless as it seems.

An old, abandoned quarries nearby, large metal grates block off ominous cracks in the earth.

They almost look like they're keeping something locked in,

rather than keeping people out. These are entrances to the box mine, a network of twisting

tunnels more than 18 miles long, which plunged to depths of up to 120 feet so unexpectedly,

it'd be easy to get lost, or worse. Mining here ceased in 1970, and parts of the quarries that had been

taken over by Britain's Ministry of Defense were sealed shut. Since then, the tunnels have publicly

been declared off limits to the public, with fire and rescue services warning people to stay

out unless they have a map and properly trained guide. Well, they probably should have specified

what kind of map, because in July 2016, four teenagers got horribly lost after following directions

provided by an app. No, not Google Maps. Pokemon Go, the mobile GPS Pokemon hunting game.

Apparently, the boys were tracking certain Pokemon when they entered the tunnels and lost their way.

They wandered around with only their phones' lights for hours until they luckily found proper signal to call for help,

just before their phones were about to die.

Three fire crews and two rope units rushed in, but that wasn't enough.

...