2x11 - The UnXplained

For centuries, humanity has been compelled to build remarkable structures that are much more than simple places of shelter or work. What makes us want to create magnificent buildings that are bigger and grander than ourselves--and last for centuries? Whether it's Stonehenge, the Notre Dame Cathedral, or the world's tallest skyscrapers--extraordinary works of engineering are evidence of a strong instinct within us that we don't fully understand. Are we trying to prove something? Or perhaps show our power over nature? Or could there be another reason that is, for now...UnXplained?