신비한사전

In the heart of Rome stands a mountain built entirely of broken pottery, with not a speck of soil. This artificial hill was created over 250 years by piling up olive oil amphorae. It wasn't just dumped haphazardly; they built retaining walls and stacked them according to a design. Amphorae stained with oil couldn't be reused even after washing, and when mixed with concrete, they turned into soap, reducing its strength. So, instead of discarding them, Rome decided to turn them into a structural material. Thanks to the interlocking shards and the binding power of lime, it still stands today, 2000 years later, without collapsing.

Above the Lion Gate of Mycenae, there's a triangular space intentionally left unfilled. It looks like decoration, but it's actually structural. It serves as a path to allow the hundreds of tons above to flow sideways, rather than pressing down directly on the gate frame. This method was used over a thousand years before the invention of the keystone arch. A nearby tomb using the same technique has a single stone over its gate weighing 120 tons, and it still stands firm after enduring multiple earthquakes for 3300 years.

Ancient Rome had over 40,000 apartment buildings for commoners, reaching up to 7 stories. However, they frequently collapsed. The emperor then legislated height restrictions, but this led to a shortage of housing for a million people. The solution wasn't to thicken the pillars, but to change the entire wall into a frame. They poured concrete, encased it with bricks, and hid arches above each door and window to divert the weight sideways. In the port city of Ostia, you can still see these arches exposed above the windows.

Ancient Roman firefighters didn't actually put out fires. Armed with axes and grappling hooks, they'd go around demolishing perfectly fine neighboring buildings. Since they had no way to get water to upper floors, they simply removed any potential stepping stones for the fire to spread. Before that, Roman firefighting was a private business. Instead of rushing to extinguish a blaze, they'd first try to negotiate a cheap sale of the burning property. Firefighting only became a state affair in 6 AD with the establishment of a standing brigade of 7,000 men.

The obelisk in the middle of St. Peter's Square isn't Roman; it was brought all the way from Egypt. How did they load a 326-ton stone onto a ship? The answer is: they didn't lift it at all. They dug a canal under the stone, floated a ship laden with rocks underneath it, and then gradually removed the rocks. As the ship floated up, it lifted the obelisk onto its deck. It was the water, not people, that did the lifting.

Behind Changdeokgung Palace is an entire mountain valley. When heavy rain falls, the water from the valley pours down all at once, and below it were the royal residences. If a stream was dug straight, the water current would become too strong, and if it didn't rain, the garden would dry up completely. Therefore, instead of letting the water flow away, the rear garden retains it in stages, like stairs. Spring water fills Aeryeonji and Buyongji in sequence, and the overflow spills over the walls and flows into Chundangji in Changgyeonggung Palace. King Injo even carved a water channel into a rock, which is now known as Okryucheon.

Hanyangdoseong was a fortress built to defend against enemies, but it had five holes at its base. It wasn't a mistake; it was designed that way from the start. The moment the wall was built around the basin surrounded by four mountains, the entire city became a giant basin. The problem was that holes also allowed people to pass through. So, iron grates were installed in each section to let only water pass, and trees were planted upstream to hold the soil in place. These water gates, demolished in 1907, reappeared after 100 years during construction work that unearthed Cheonggyecheon Stream.

The stone courtyard in front of Jongmyo's main hall is wide enough to fit an entire soccer field, yet it has no roof or drainage. Still, even when torrential rain pours down, the water doesn't pool. The secret lies in the unsightly stones laid on the ground, called 'bakseok'. If they were polished smooth, they'd be slippery on rainy days and blinding in the summer sun. That's why the surface was intentionally left rough, and stones of various sizes were fitted together. The tiny gaps between them allow the rainwater to be divided and absorbed into hundreds of channels. In essence, the ugliest stones have endured the longest.

In a subway fire, it's not the flames that get you, but the smoke. Hot smoke rises, and people have to escape upwards via the stairs. It's like a race between smoke and people for the same passage. That's why modern subways push air towards people instead of sucking out smoke. By increasing the air pressure on the stairs compared to the surroundings, smoke is prevented from entering in the first place. If the pressure is too high, the doors won't open, so they've even installed lids that automatically open when the pressure exceeds a certain point.

The western side of Gyeongbok Palace was originally a marshy area where water seeped out when dug. The pavilion built on top of it actually tilted to one side. Pumping out the water was useless because it wasn't rainwater from the sky, but water pushing up from underground. So, instead of removing the water, Joseon gathered and contained it in one spot. They dug out the entire marsh and made it the lowest point within the palace grounds, causing all the surrounding water to flow there, leaving the foundations of other buildings dry. The excavated soil wasn't discarded but became a hill behind the Queen's chambers.