What has been the most exciting part of designing underground stations?

Question: What has been the most exciting part of designing underground stations?
- Keywords:
  design,
  exciting,
  underground station
Asked by spinachleafolive to Emma on 18 Mar 2016.
- Emma Bradley answered on 18 Mar 2016:
  
  I think learning about all the different things that go into them and then seeing them built! There are so many different engineers involved who are all experts in different things, so I get to learn about all the fire engineering and security and ventilation and acoustics that are considered for the design of the station as well as thinking about my bit, which is the structure.

Question: What has been the most exciting part of designing underground stations?