Here at the Royal College of Physicians the museum team like to talk a lot about our magnificent modernist building, its architect Sir Denys Lasdun, and our Grade I listed status.

It was only recently that I came across an article listing the nine post-war Grade I listed buildings. Just eight more in the whole of England. I now think we should be talking up our spectacular headquarters considerably more.

So here are nine reasons why the RCP building is so special and why you should call in to have a look during Open House London in September:

1. It looks like an ocean liner pulled up next to Regent’s Park…

2. …but inside is an amazing 17th-century oak-paneled room

3. There are massive windows: the biggest possible to make in the 1960s...

4. ...and tiny windows: Lasdun’s arrow-slits are everywhere

5. A lovely John Hoyland 1960s abstract painting - reputedly bought to ‘match the carpet’

6. Shadow gaps

7. A lamppost outside - so special that it is Grade II listed all on its own.

8. We have gothic vaulted ribs (and not just for lunch)

9. 17th-century human remains hang on the wall, inspiring Lasdun to create the building's circulatory flow

There are plenty more: what would you choose as the tenth?

The building is a bustling conference venue during the week, so Open House London is your annual chance to explore every arrow slit, ceremonial staircase and central void undisturbed, take a free expert tour and have a nice cup of tea and a cake at the same time.

Emma Shepley, RCP senior curator