Real Madrid in 2009 to Chelsea's 2004 spending spree and PSG's bargain basement collection of all stars last year, more than a few clubs can stake a claim to having had the ultimate transfer window.With that in mind, we're taking a look back at some of the best windows at a single club in the last 25 years, starting with that iconic summer at the Bernabeu 13 years ago. Signing Cristiano Ronaldo, Kaka, Karim Benzema and Xabi Alonso might sound like something out of FIFA Ultimate Team, but that's exactly what Real Madrid did in the summer of 2009.