> 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).
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).