https://en.wikipedia.org/wiki/Scott%27s_Grotto
The V&A has a huge Four-Poster bed named The Great Bed of Ware, that seems to be a rare survivor.
https://en.wikipedia.org/wiki/Great_Bed_of_Ware
Large enough for four couples apparently, one assumes that was down to cold winters.
https://en.wikipedia.org/wiki/Shell_Grotto,_Margate#Origins
> A member of the Kent Archaeological Society analyzed the grotto and concluded in 2006 that it was likely a mediaeval denehole, a small chalk mine, reworked and decorated in the 17th or 18th century.
There are multiple buildings in my village older than that (and the core of the church is centuries older).