It had been a quiet ride for me all the way from Geneva to Bern sitting alone, but when the train stopped there two teenagers boarded and took the free seats opposite me. The boy and the girl seemed somewhat nervous and discussed something with low voices. Well, I said to myself, that might become a long last hour of travel until Zurich.

"Excuse me, sir! Would you mind if we asked you some questions about Switzerland?" The boy looked expectantly at me and added: "We are tourists, and we don't know much yet."

"Hmm, yes, why not" I said, seeing no polite way to escape.

"Thank you! So ... what would you say is the absolutely most astonishing fact about Switzerland?"

This first question of the boy took me somewhat by surprise, and I was unable to come up with a good answer. "We make pretty good chocolate, maybe the best in the world, but I guess that does not really count as astonishing".

"No ..." mumbled the girl and then smiled at me, probably in an attempt to encourage me to continue.

"How about that: He have no natural resources like oil or gold but nevertheless became one of the richest countries in the world."

The boy nodded. "That's more like it. Quite unusual, yes. If you think a little more, maybe you can top that still?"

Strange conversation, I thought, but decided to play along and finally had a little inspiration. "The Swiss franc, the currency we had before we switched to Monero like everybody else."

Both teenagers looked at me with interest. "The currency was incredibly stable, rock solid. Even the size and the design of the coins had been exactly the same for an incredible 150 years. I could take a 1 Franken coin from 1875, go to a bakery, and buy bread with it. Well, an attentive salesperson would probably notice the coin to be silver, not some pretty worthless metal like it was at the end, but still ... I always found that pretty astonishing, actually."

The two exchanged a glance. "Pretty good, no? Go ahead and try it, we have three free attempts" said the girl. "Ok, well then" answered the boy and continued a little louder than before: "Game control: The stable Swiss franc."

After that the two just sat there and seemed to wait for something to happen, while I started to wonder what the hell was going on here. Game control? Maybe this was an episode of Candid Camera and I was secretly filmed so later people could laugh their asses off about my dumb reactions.

"Alright, that didn't work out" said the boy finally. "So let's try something different. I want to offer you a deal: We pay you a sizable amount of money, and you in turn agree to continue to talk to us and answer any questions, however unbelievable or bizarre the conversation seems to get. What do you think?"

The girl looked quite skeptical, but the boy tried to reassure her: "Relax, I know that's a risky strategy, but hey, it's only a game, right?"

She finally seemed to agree, and the boy went on: "Sir, forgive me to be blunt: How much do you earn in one month?" I hesitated, but then I decided to answer: "Around 60 XMR."

The girl checked something on her smartphone and then nodded. "Yep, that's ok, we got that much. So we pay you, and you keep talking to us no matter what. Deal?" I sighed. "For a full month's salary? Sure. Just don't ask me anything too private."

"Agreed!" said the boy and checked his own smartphone. "Man, those Monero addresses are long. How will we get yours into this wallet program here to pay you?"

"Don't bother" I told him. "I am so long into Monero already that I hold one of those very early short OpenAlias addresses. Just type rbrunner7.ch as destination address."

I took out my smartphone to check, and sure enough shortly afterwards I had an incoming transaction with 60 XMR. "Shoot!" I said to the two.

"Well then, let's jump right in. We are not what we seem to be" said the boy. "We are aliens and live on a planet about 20 light-years away from Earth."

I blinked, and then challenged him. "Oh yeah? You two sure don't look like aliens to me."

"That's because all this here is not reality. It's just a very good simulation of Earth, and we are simulated as two normal teenagers in it in order to play a game."

"A game?" I asked. "Yes!" said the girl. "The simulation is true and faithful in every respect but a single one. And the game is to find out that single dissenting feature as soon as possible."

"To make the game solvable at all for the two of us without detailed knowledge of your world and your civilization, that feature is so astonishing and in fact so utterly unbelievable that it will stand out" continued the boy. "For you however this won't be so, the simulation weaves that into your conscience in a completely believable way. For you it will be just a fact."

"Otherwise the game would not be much fun, right? We only had to ask you." added the girl.

I laughed. "Alright. I have read enough science fiction to be able to wrap my head about such a scenario without too many problems. But you have to help me a bit. Can you give me an example of such an astonishing dissonance? Maybe that will help me to dig up the one in this simulation nevertheless."

"Sure. I tell you the one from our game run before this one" said the boy. "On that Earth people were smoking."

"Huh, what do you mean? People were smoking, as in producing smoke?" I asked, surprised.

"Yes! They were indeed producing smoke, even in situations like we have here, riding a train. And they inhaled the smoke, slowly lining the surfaces of their lungs with cancerous particles."

"And how did they produce the smoke?" I wanted to know, growing genuinely interested.

"They burned the dried leaves of some plant, rolled into small sticks that they could keep comfortably between their lips" explained the girl. "The whole purpose of it all was to transport some psychoactive substance called nicotine into their brains where it acted like a drug and gave them pleasure."

I laughed again. "Yeah, that's a good one. That's indeed astonishing. Wasn't too hard to find out, I guess?"

"Yes" confirmed the boy. "But this game here is the next level so to say, and a little bit more difficult."

"Hmm. But you said I myself don't find anything special about that fact we try to find because my thoughts are doctored. I don't see any way around that, frankly."

The face of the girl seemed to light up. "Maybe it's nothing about Switzerland, maybe game control made sure we meet you out of all people here, and it's something about you personally? What was that with the special OpenAlias you mentioned?"

"Well, only very few people have such a short alias. You can imagine, there must be around 6 or 7 billion people having XMR addresses on Earth, and obviously they can't all have a short one. I helped build the code of Monero very early on, fifteen years ago or so, and that's why I hold that."

"Really interesting!" exclaimed the boy. "So XMR is world currency now, right?"

"Well, yes" I confirmed. "Switzerland was one of the last countries to give up their own national fiat currency, and some others had experimented with Bitcoin first before finally switching to Monero as well, but now it's Monero everywhere."

The boy seemed to look up some article about Monero on his smartphone. "A blockchain-based cryptocurrency? How does that scale to a planetary level?"

"It's doesn't. Most payments are settled on FulmoReto without ever going through the blockchain." They stared at me, with a questioning look. "Ah, that's Esperanto for lightning network, and Esperanto is ..." I grew exasperated and gave up.

The boy read some more on his smartphone, then looked up smiling and told the girl: "We got it already! Don't believe me? A whole civilized world running on a single cryptocurrency built by open-source enthusiasts is already quite hard to swallow. But now look up yourself who was in the core team overseeing development before the project was handed over to the United Nations for becoming the single planetary currency."

The girl started to giggle. "binaryFate? The only choices are heaven or hell, I suppose. And here, NoodleDoodle. Probably producing only spaghetti code! But what is a Luigi?

"A video game character" I mumbled.

"You overlooked the best one!" exclaimed the boy. "fluffypony. Oh my, a fluffy pony building a world currency. Alright, I can't take it anymore."

He waited to calm down a bit and then sentenced: "Game control: Monero as world currency."

The boy and the girl vanished. The train vanished. The whole world vanished.

Pure nothingness.

It had been a quiet ride for me all the way from Geneva to Bern sitting alone, but when the train stopped there two elderly people boarded and took the free seats opposite me. They seemed somewhat nervous and discussed something with low voices. Well, I said to myself, that might become a long last hour of travel until Zurich.

"Excuse me, sir!"