Why buildings fall down?

Early this year, a building in Bangladesh collapsed to the ground, killing 150 people who worked or shopped there. On that day, there was no earthquake, no wind, no plane crash, the 8 story building just smashed onto the people who were there, minding their own business. After the catastrophic failure,  people blamed all sorts of things, including the soft soil that the building was sitting on, lousy construction practice, poor country that couldn't afford much steel reinforcing bars in a concrete building, and ignorant people who load up their factory floor far exceeding it can carry... With all that, still, why does buildings fall down? 

The answer is simple, all building fall, period.  There were  seven wonders in the ancient world existed more than 2000 years ago, including the Great Pyramid of Giza, the Hanging Gardens of Babylon, the Temple of Artemis at Ephesus, the Statue of Zeus at Olympia, the Mausoleum at Halicarnassus, the Colossus of Rhodes, and the Lighthouse of Alexandria. Till today, the only wonder still in existence is the Pyramid of Giza. And over years, even those solid limestone blocks of the pyramids were damaged by wind, rain, looters and tourists. Eventually, it would still fall, deteriorate into the desert, or even give away to the new highway. Nothing is immortal. 

The reason? There are basic laws that governs the universe that we lived in. One of them is Newton's law of universal gravitation. If something is raised up high to cover our head or shelter us through rain or the torching sunlight, there is a gravitation force that want to drag it down until it hits the ground and has nowhere to go. This is the reason we never have roof floating in the air. And it is also the reason that we have walls, columns and beams in our buildings so the roof has no way to hit the ground.

Sounds easy, right? If we take care of gravity then nothing would fall? We forgot another important governing issue, the second law of thermodynamics. It states that the entropy of an isolated system never decreases, because isolated systems spontaneously evolve toward thermodynamic equilibrium—the state of maximum entropy. The universe, as a isolated system, contains particles, stones, trees, bodies and minds, each of those are animate, self-active and free. The free matters in the system, statistically, will spread out and go from order into disorder or chaos. A building is a organized matter with a designed order. but the matters, as part of the nature, will go into disorder since that is the stable state. In fact, all we have to do is nothing, and everything deteriorates, collapses, breaks down, wears out, all by itself -- and that is what the second law is all about. Natural force such as fire, explosion, erosion, corrosion, earthquake and  tsunami, they don't create order, they destroy it.

So, this is what engineers do, we work with nature, to put certain matters (building material) in order. Then we preserve the order temporarily, so our roof will continue to be our protection against rain and sun, not crashing down to our heads.