A family member worked at the Wellcome trust growing up. I spent a lot of time there as a child before the place had a refurb and a new building. I can tell you that there are tunnels underneath that link to other buildings from 183 euston road, the original pillared site.  The surrounding buildings are all UCL and UCH campuses. They are right opposite and connected to University London Hospital.   In my experience everyone was really quite nice, but Henry Wellcome himself was a very strange man. Dead obviously, but they insist on keeping his sex instrument museum up as a fixture, even in the new site. The man toured the world and in his travels collected a lot of bizarre sexual instruments from other cultures. They are openly on display. https://www.rammuseum.org.uk/past-exhibitions/intimate-worlds-exploring-sexuality-sir-henry-wellcome-collection/ "Between 1900 and his death in 1936, the billionaire pharmaceutical giant Sir Henry Wellcome amassed over a million objects from across the globe and for his museum of medical history. A substantial proportion of these related to human sexuality." Actually come to think of it Henry deserves a dig...