Ski-Tube.

[siologen]

When an underground Rapid Transit System thats 'abandoned' for half the year is between 500 and 800km away (from your starting position), you dont rush out to explore it. You wait 11 years, explore some Toronto Subway, a bit of Paris Metro and some London Underground

Comments

[radovar]

I think everyone has objects in the nearby which he don't explore for years because he is sure that he can do it at any time :)

[theodosos]

Yep, the nearest objects are usually unvisited for ages