Our house (Americans) is from 1909 and we think its crazy how old it is.
Our friends from the Netherlands came to visit and informed us that the next day they would visit DC (2-3 hours drive) and then swing by the upper peninsula of Michigan the day after (20+ hours).
A couple of weeks ago I had a pint at the Kirkstone Pass Inn [0] and was thinking about Triggers Broom [1]. The foundations of the core of that Inn date back to 1496, but clearly the carpets aren't that old.
At what stage does a building become new? Lincoln Cathedral was built in 1072, but rebuilt in 1185. The Man and Scythe (a pub) in Bolton was rebuilt as recently as 1636, but the front of the building is only 100 or so years old. The cellar probably predates the 1636 year, and there was a pub of that name in 1251. Exact details of when old buildings (which are still in use) are rebuilt are typically lost to history.
[0] http://www.kirkstonepassinn.com/about.htm [1] https://en.wikipedia.org/wiki/Ship_of_Theseus
* https://news.ycombinator.com/item?id=12326425
Quite a long way in the past.
* https://news.ycombinator.com/item?id=17496989
* https://www.bbc.co.uk/news/uk-wales-44806069
* https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-4...
And then there are the forts where the walls were melted - by accident or on purpose - nobody is really sure:
“No one, not even you, will remember if we were good men or bad, Why we fought or why we died. No, all that matters is that two stood against many. That's what's important.”
— Conan the Barbarian (1982)
Was it burned down by enemies (a Viking siege?), by accident or on purpose. Nobody knows.
https://en.wikipedia.org/wiki/Green_Castle,_Portknockie
And there is also the (crazy) idea that I've had since I was a kid that the Tap o' Noth is Tolkien's Weathertop ;-)
A tour guide somewhere in the US southwest stands in front of a building and says "This building is one of the oldest in the territory, a hundred and twenty years old. Think of that folks, a hundred and twenty years old."
A voice from the back of the crowd says, "I can't wait to get back to Damascus and tell them."
[edit: changed initial "And" to "An".]
There is also social housing, build in the 16th century by one of the top 3 wealthiest people in modern history. Still in use today, about 1€ a year rent.
Also, AD / BC wasn't devised until 525 AD, and zero was common at that point, so that can't be the reason: https://en.wikipedia.org/wiki/Anno_Domini
EDIT: Apparently I'm wrong :)
Neither the concept nor a symbol for zero existed in the system of Roman numerals. The Babylonian system of the BC era had used the idea of "nothingness" without considering it a number, and the Romans enumerated in much the same way. Wherever a modern zero would have been used, Bede and Dionysius Exiguus did use Latin number words, or the word nulla (meaning "nothing") alongside Roman numerals.[1][3][4] Zero was invented in India in the sixth century, and was either transferred or reinvented by the Arabs by about the eighth century. The Arabic numeral for zero (0) did not enter Europe until the thirteenth century. Even then, it was known only to very few, and only entered widespread use in Europe by the seventeenth century.
Some of the buildings have been updated a bit, however, at Oxford and plenty of other university/school towns in England there are buildings that are still used today for their original teaching purposes, having been built many centuries ago way before the Columbus story of 'discovery' was written.