So I've shared this fascination with life finding its way in the most obscure of circumstances. 
I'm actually going to officially decline the possibility of winning, my post is not so much finding the plants in the cracks of the world, but more a demonstration of their limits in this photo I took around the Annapurna mountains in Nepal:
This beautiful, earthly trifle shows a distinct tree line where the trees die off for some reason, followed by baron mountain and finally, ice. Obviously.
But I always assumed the trees died off at this point due to a lack of oxygen until I visited Nepal and reachedd heights of 5,000 metres or so. I was still breathing, so how come plants couldn't?
It turns out that the tree line - its official name - is actually a result of temperature.
At some point, the temperature hits a point where the cells that make up the organism can no longer function and build. Sure, there may be warm days in the summer, but overall the ratio of days that share enough warmth simply aren't enough.
For trees it's even worse, with their vast canopies casting shade on the ground below making it even colder, which is why you might see low-lying shrubs at much higher altititudes.
The temperature factor also explains why the tree line is not globally identical. Depending on whether you're in the equator or the arctic can bring a treeline right down to 0m (Quebec... Thanks, Labrador Current) and up to 5,200m (Bolivia). For the most part, plants generally cease to exist long before the oxygen levels become too low (then again, some animals bizarrely manage to completely defy these limitations, as discussed in a two-part post I once did).
So there you have it. Unless you live in the peaks of Tibet, given enough time your house will overgrow with shrubbery and trees. You can count on it.
Cool hat, I know.