Firewalking is the act of walking over blazing hot coals without being burned--or at least badly burned. In some cultures, doing so is a religious rite that serves as a test of faith. Physics teacher David Willey explains that it's possible because coarse coals are poor conductors of heat:
It would seem then, that a firewalk of short length is something any physically fit person could do and that it does not need a particular state of mind. Rather, it is the short time of contact and the low thermal capacity and conductivity of the coals that is important, and it is not necessary for the feet to be moist nor callused, although either may be of slight benefit. Longer walks appear to be possible if a layer of insulating ash is allowed to build up on a well packed down bed, where the temperature has been allowed to fall significantly from what it was when the coals were at their hottest.
LEGO bricks, however, are a different matter entirely. As any parent can tell you, a LEGO-strewn floor is a minefield. To promote The LEGO Movie, Bull Moose, an entertainment shop chain in Maine and New Hampshire, developed a firewalking path covered with LEGO bricks. Will you dare to take of your shoes and walk across it?
-via Blazenfluff