It was a series of four interviews with the different HR departments throughout the company. It went by much faster than I expected and the employees that interviewed me were very welcoming and friendly. I first had a phone interview with one of their associates located in London, and then was asked to come in the following week to their DC office for a series of interviews (4 total, each 1:1, with the exception of one being 1:2, and one via skype). It lasted a few hours, and many questions were repetitive from one interview from the next.