By Chris Skeldon 
There is a German town in Bavaria, with a population of about 20,000, living surrounded by about 72,000 tons of diamonds… embedded in the walls of almost every building.
While building the city, which was first mentioned in records in the 9th century AD, the colonists did not realize that the stone they used was studded with millions of tiny diamonds, in a concentration unseen anywhere else in the world.
The Nordlingen website explains this phenomenon: These gems were created by an asteroid that fell to Earth 15 million years ago, and their diameter was less than 0.2 mm, i.e. barely visible to the human eye.
However, according to the British newspaper, the Daily Mail, locals were not aware of this amazing phenomenon until the 1960s, when two American geologists, Eugene Shoemaker and Edward Chao, arrived in the city.
Although the perfectly circular city (similar to the fairy tales featured in the 1971 version of “Willy Wonka & The Chocolate Factory”) appears to fill an entire crater, Nördlingen is actually located inside the 26-kilometre-wide Nördlinger Ries crater. The city’s circular shape is pure coincidence. About 15 million years ago, a kilometre-wide asteroid, moving at 25 kilometres per second, hit the Earth with such force that it created a giant crater.
The people of Nördlingen assumed that the Nördlinger Ries crater was the result of a volcanic eruption. But Shoemaker and Zhao suspected that the crater was caused by an asteroid impact. Once they visited and saw that the church walls were filled with clusters of tiny diamonds, they knew their theory was correct.
Carbon bubbles inside the rock were transformed into tiny diamonds under the pressure and heat of the explosion. “There are some places in the world where this type of material from asteroids has been used in buildings, but not even close to this case,” Stefan Hölzle, a geologist and director of the Nordlingen Ries Crater, told the BBC. “And here it was used to build an entire city.”
The St. George Church in Nördlingen alone is believed to contain 5,000 carats of precious stones. As you climb the stairs of the Gothic church tower, the worn stone steps appear to glow in the sunlight, bringing unexpected flashes of light to what should have been a dark grey climb to the top. “That’s because the entire tower is made of Soviet stone and has tiny diamonds inside,” explains Horst Lehner, the tower’s caretaker. “Luckily they’re so small, otherwise the tower would have been demolished long ago,” he jokes.
Holzl also noted that NASA astronauts from the Apollo 14 and Apollo 16 space missions visited Nordlingen before their lunar missions to learn about the types of rocks they might find in space.
However, the people of Nördlingen will not be rich. Although diamonds help keep this city shining, they have no economic value.