We all know the city of Rome has been around a long time. However for about a year, around 190 AD or so, Rome didn’t exist. Why?
The more details you give, the more you win.
Owing to an incident with an elastic band and a pencil, a Google employee accidentally deleted it from the search database. Attempts to find “Rome” turned up entries relating to “Rhine”, “Westphalia”, “Damascus” and “Jitterbug”. This omission was not noticed until two years later. The employee was disciplined (forty lashes) but not dismissed.
(Is that trivial enough?)
There are more details, but I thought the following was topheavy enough (from roman-emperors.org):
"The coins issued in his first year all display the triumphant general, a warrior in action who brought the spoils of victory to the citizens of Rome.[[3]] There is a great deal of evidence to support the fact that Commodus was popular among many of the people, at least for a majority of his reign. He seems to have been quite generous.[[4]]. Coin types from around 183 onward often contain the legend, Munificentia Augusta[[5]], indicating that generosity was indeed a part of his imperial program. Coins show nine occasions on which Commodus gave largesses, seven when he was sole emperor.[[6]] According to Dio, the emperor obtained some of this funding by taxing members of the senatorial class.[[7]] This policy of munificence certainly caused tensions between Commodus and the Senate. In 191 it was noted in the official Actus Urbis that the gods had given Commodus to Populus Senatusque Romanus. Normally the phrase Senatus Populusque Romanus was used. [[8]] While the Senate hated Commodus, the army and the lower classes loved him.[[9]] Because of the bad relationship between the Senate and Commodus as well as a senatorial conspiracy,[[10]] Rome “…was virtually governed by the praetorian prefects Perennis (182-185) and Cleander (186-9).”[[11]]
Commodus began to dress like the god Hercules, wearing lion skins and carrying a club.[[12]] Thus he appropriated the Antonines’ traditional identification with Hercules, but even more aggressively. Commodus’ complete identification with Hercules can be seen as an attempt to solidify his claim as new founder of Rome, which he now called the Colonia Lucia Annia Commodiana. This was legitimized by his direct link to Hercules, son of Father Jupiter.[[13]] He probably took the title of Hercules officially some time before mid-September 192.[[14]]"
Rome burned in 190 AD and Emperor Commodus had it rebuilt and renamed in his own honor Colonia Commodiana, IIRC. A year later he was strangled in bed, and the Senate condemned his memory and restored the name Rome to Rome.
To say that it “didn’t exist” is pushing it, perhaps… It was just called something else.
Edit: Ahh, I see that Nano is already there. 
But speaking of Commodus (who was a terrible emperor, following the five “good” emperors), although he was condemned by the Senate, Commodus’ successor had his memory restored and Commodus deified, just a few years later I think. Something to do with Commodus’ family. Commodus was famous for his large harem, I believe.
Bloo, my source says Commodus was strangled in his bath by a wrestler named Narcissus.
Oh, those Romans.
Well, he slept in his bath, didn’t he. 
At least I didn’t google it, like some people…
Oh, just pick up your diamonds, darling. I’m sure you can have them reset in a jiffy. 
I couldn’t be too exact or it would have given away the answer. Yes the collection of buildings making up the city did exist but a city called Rome didn’t exist.
Really now. I can just imagine the conversations.
Vestus: Hey sweetie! I’m taking the chariot into town for some new spikes. You need anything?
Vesta: Where?
Vestus: Rome.
Vesta: Silly goose! There’s no such place. Do you mean Colonia Commodiana?
Vestus: (rolls eyes) Yeah. And while I’m there I’m gonna do as the Colonia Commodianans do and have myself a brewski.
So, Commodus was flushed?
I know, I know. His reign was down the toilet.
But I get to thinking about induced asphyxiation by a wrestler (named “Narcissus”, no less) while in one’s bath. Almost sounds like a “sporting event” ahem gone horribly wrong. Maybe the emperor was “flushed”, so to speak. At least until he went blue. Heh.
Oooh, you’re a quick one. I wondered if anyone would pick up on the possible double-meaning of the word “flushed”.
Quick, schmick. Do you have any idea what it’s like dragging around a dictionary all the time just in case you post?
(I do occasionally need a Latin dictionary when reading this forum. Luckily, I found this Univ. of Notre Dame site: [u]Latin Dictionary and Grammar Aid[/u].)
With people like you and Bloo on board, I scramble to keep up.
(schmick, btw, is not a word.)
(But it is a name.)
Thank you, Em, but I remain an obdurate pre-Gutenbergian, and regard printed hard copy as effete. I can’t afford manuscripts of Webster’s though, so I have to knuckle under.
Somehow I doubt that very much.
Okay, I take that back.
What, you use papyrus scrolls?
Note the absence of the word “to.” Hard evidence of scrambling.
Schmick is a word? 
Schmick’s a whole dictionary full of 'em.
Typos, schmypos, Em. Let’s not flog ourselves too hard over them; takes away jobs from deserving dominatrixes and dominatrons.
Or was that a quaint example of Marylandian dialect?
Just giving you a hard time, Em.