The Gardner's Inn

This is the Gardner's Inn in Blackheath. 
Built by a former convict, it is the oldest continuously licensed hotel trading in the Blue Mountains. 
Charles Darwin stayed there in 1836 and he reported it was "very comfortable". He also wrote in his diary that nearby Govetts Leap was "one of the most spectacular chasms he had seen on his trip around the world".
It is described as being "an important focus of social activity in Blackheath from 1931 to the present day", which is very true as it is now the location of "The Office" frequented on Saturday afternoons by Mr isbi and his punting mates.
The website may be exaggerating a bit by describing it as "Luxury Accommodation" but I suppose that is relative and I'd have no hesitation staying there. 
You can get rooms with en-suites but the "Standard Double (or Bunkbed) with shared bathroom is thoughtfully equipped to meet your needs. While promoting cost-effectiveness, the shared bathroom adds a communal touch fostering a friendly atmosphere among guests" sounds interesting.

Thanks for hosting this week's wide challenge with the theme of "interesting building" Bob.