It's been a productive summer in the transfer market for Chelsea.
Jose Mourinho has strengthened his squad with the addition of Diego Costa, Filipe Luis and Cesc Fabregas, while the Blues have recouped considerable funds with the sale of Romelu Lukaku and David Luiz for a combined £78 million.
Of course, big-money signings are not always a recipe for success—something the Blues are only too aware of.
Indeed, things haven't always been so merry for Chelsea when it comes to transfers. In the past decade, for every success story, there has been a failure.
Bleacher Report takes a look at the top five.