Why do banks have so many staff?

Rabobank HQ interior

I had my first visit to Rabobank’s new headquarters in Utrecht last week (locally dubbed the ‘binoculars’, due to the exterior look, while inside it is undeniably Dutch-style funky - http://www.sander.nl/en/sander-architecten-international/clients/companies/rabobank-nederland.aspx).


However, my meeting was in one of the bank’s other offices in the city, accessed by a Rabobank people-carrier, shuttling between the two complexes. Which gave me time to ponder, why do banks have so many staff? The new HQ certainly looks large but it is insufficient to house all of the bank’s staff in Utrecht. In total, Rabobank has 61,000 full-time employees. What do they all do?