262 votes
Accepted

How does a species who cannot distinguish left from right build their cities?

Fran is a naturally subterranean boring worm-like creature. Her cilia enable her to move forward and rotate. On her homeworld, the tunnels are bored with ridges or grooves that serve as affordances ...
Thriggle's user avatar
  • 2,567
192 votes

How can I build a door to repel a horde of zombies?

Human engineering can, 100%, keep out a horde of zombies. In The Walking Dead things fail because if they didn't the show would be boring. In real life, there exist castle gates hundreds of years old ...
AndreiROM's user avatar
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135 votes
Accepted

What is the minimum radius of a circular corridor for the walls to appear straight?

TL;DR: Really, really big (exact numbers below) Seeing the wall "crossing" is hardly the issue. Seeing the outer wall bend even slightly toward the inner wall - looking as if the hallway gets ...
Weckar E.'s user avatar
  • 1,930
132 votes

The 10,000 year skyscraper

Build a Pyramid The Pyramids are halfway to your desired 10,000 year life span already. They are a little worse for wear, but they are definitely still standing. First, lets assess the criticism ...
kingledion's user avatar
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115 votes
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How can I build a door to repel a horde of zombies?

We humans are pretty good at building gates to keep people out. We've been doing it for a long time for military purposes and to stop thieves. Why Do We Have Gates? Because there has to be some way ...
Schwern's user avatar
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100 votes
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How would someone destroy a dam in a world without explosives?

Forts using stone, rock and earth walls as fortifications (and in some cases, still standing !) were often attacked during sieges. Such a wall has much in common with a dam. To breach such a wall ...
StephenG - Help Ukraine's user avatar
90 votes

How does a species who cannot distinguish left from right build their cities?

There are a few languages on earth that don't have words for relative direction. Instead of they use absolute the directions North, South, East, and West to describe the positioning of things. For ...
sphennings's user avatar
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85 votes

Why would a civilization outfit buildings with separate portals for entering and leaving them?

The body shape of the aliens makes it difficult to pull doors open, but they can easily push doors open (or vice versa). Have you ever tried to get through a door with both hands full? The aliens' ...
o.m.'s user avatar
  • 114k
67 votes

Why would a civilization outfit buildings with separate portals for entering and leaving them?

Your society has a hypermartial warrior culture. The double-doors eliminate the problem of accidental rudeness and slaughter. If you were to attempt the use of a door at the same time as me, one of ...
Nij's user avatar
  • 740
67 votes

How would someone destroy a dam in a world without explosives?

A more devious scheme to bring a dam down: A secret second dam above the main target dam. You simply install a second dam above the main dam (as high as possible ideally). You reduce the flow ...
Thorsten S.'s user avatar
  • 14.7k
66 votes

Dungeons for Real: 1. The Bottomless Pit

Indoor skydiving Indoor skydiving simulators are popular and not particularly difficult to build. A person who falls into a "bottomless pit" would feel like they're falling faster and ...
Alexander's user avatar
  • 42.2k
64 votes

How can I make the supporting pillars of an underground city less obstructive?

Mirrors, greenery, sculpture and waterfalls. You can’t hide these things. The best you can do is make them more easily ignored or more pleasant to look at. Mirrors provide the illusion of space and ...
Joe Bloggs's user avatar
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59 votes

The 10,000 year skyscraper

Self-healing concrete. It works by embedding tiny capsules in the concrete containing bacterial spores. When the capsules are broken by water penetrating the concrete, the bacteria are released and ...
Werrf's user avatar
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57 votes
Accepted

Why would a modern city with a warm climate have a skyway system?

Reasons: Skyways can be airconditioned and so cooler Skyways can be sheltered from rain and so more pleasant Skyways are safer than walking on the streets, where the cars are; separation of cars and ...
Mary's user avatar
  • 28.3k
56 votes

How to design a fortress in a mountain to keep it hidden, but still easily defensible?

From walking by casually? Easy. If you assume it needs to remain hidden from the valley below, you just need to place any entrances, windows, etc., behind a curve. I think your biggest issue by far ...
Mormacil's user avatar
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55 votes
Accepted

What architectural tricks can I use to add a hidden floor to a building?

The easiest places to hide an extra level are the bottom and the top. You can have all the subbasements you like, though they come with neither a view nor natural light. Either of these can get ...
Separatrix's user avatar
  • 118k
51 votes
Accepted

How to design a fortress in a mountain to keep it hidden, but still easily defensible?

Consider the real world underground city of Derinkuyu in Turkey They stumbled on a simple solution, a giant stone disc in a groove for a door. Easy to move and brace from the wide interior room but ...
John's user avatar
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51 votes
Accepted

How would you make a door that could still be opened a million years later?

Sand door. The door is a hole in the floor. The hole is full of sand. If you dig it out, it connects to another hole in the floor of the adjacent room. The door is made of sand. The sand will keep ...
Willk's user avatar
  • 304k
50 votes
Accepted

What is the point of introducing puzzles into tomb design if you don't want anyone to disturb whatever hidden?

For three reasons: you build the tomb on the behest of the owner. You still need to add their body and all their possessions to the tomb later! So you want a lock that can be opened to do your job. (...
Demigan's user avatar
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49 votes

How would one attack or lay siege to a flying castle?

Let's revisit the premise that the sky-castle has a year's worth of water stored on it. As a corollary to this premise, we should assume that the stored water won't become stagnant or otherwise ...
user535733's user avatar
  • 28.9k
48 votes

Why would a civilization outfit buildings with separate portals for entering and leaving them?

Feng Shui! In the traditional Chinese Architecture: The main gateway entrance into the courtyard house had two red doors; it was located on the eastern part of the south side conforming to the ...
Matthieu M.'s user avatar
  • 3,113
47 votes

What is the minimum radius of a circular corridor for the walls to appear straight?

SRM points out that even in a circle long enough that you won’t reach your starting point again if you're walking for an hour, and where you can’t see very far, one can still tell that the walls are ...
JDługosz's user avatar
  • 69.4k
45 votes

Building a bridge from one side

Make a balloon. All you need is some decent silk/linen, ropes, some basket, and then something to heat up the air inside. Heat the air, unstick the balloon, but take some rope with you so you won't ...
Antoine Hejlík's user avatar
44 votes

How can I make the supporting pillars of an underground city less obstructive?

Build skyscrapers around them If you can't hide, camouflage. Turn the pillars into the city's skyline by building a unique looking skyscraper around each pillar.
Halfthawed's user avatar
  • 40.4k
43 votes

How would one attack or lay siege to a flying castle?

From a safe distance, your sappers excavate a tunnel. The tunnel leads to the tether point of the castle's anchor chain. Bring the tether down into the tunnel from below. Winch it along the tunnel....
Willk's user avatar
  • 304k
42 votes

Passive Cooling Techniques for Apartment Buildings

It seems you've already done the research into the vernacular architecture of the sort of region you're describing, but there's one critical factor you've overlooked and it's hard to emphasise how ...
Separatrix's user avatar
  • 118k
41 votes

How does a species who cannot distinguish left from right build their cities?

How about the rationality of object persistence? She doesn't have to know left from right; she knows the lemonade stand exists and will continue to exist if it is out of her sight. Infants know this ...
Amadeus's user avatar
  • 34.7k
39 votes

Why would a modern city with a warm climate have a skyway system?

Choosing an answer from the real world: because you have a lot of pedestrians, and without the elevated walkways they would effectively block all motor traffic. This is the main reason for Tokyo's ...
FuzzyChef's user avatar
  • 2,318
38 votes

What are the feasible means of keeping a space station existing and operational for thousands of years?

You have solar power, I presume you have reasonably intelligent robots, the solution is to take a clue from biology: Constantly, whether it is needed or not, replace every molecule of the space ...
Amadeus's user avatar
  • 34.7k
38 votes
Accepted

Destruction by design - how best to go about crafting a ruined landscape?

Start with the people then the city then the ruins Cities always arise from the culture and situation of the people who built it. Their priorities will be expressed in what buildings are where and ...
Green's user avatar
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