In Calif, creating Calendar item for future "London Reservation for 9AM", what should event time zone be?

I live in Pacific Standard Time zone. I'll be traveling to Europe this summer to multiple time zones. In preparation, I'm creating lots of calendar events for flights, trains and dinner reservations that have times specific to European cities.

(I do have "time zone support" turned on in Calendar.)

What should the individual event "Time Zone" setting be for all these future European events? (They defaulted to "Pacific Time".)