8. Death races
While throughout most of human history we have been a species hell-bent on survival, suddenly things went awry. Now we have a multitude of races where mud, obstacles and punishing circumstances bring runners to their knees begging for mercy, and these events are more popular than ever. One of the most drastic ones, the Death Race, was “built to break the weak of body and mind!” Given that only 10 percent of the competitors complete the 48-hour race, it seems to be working.