The iCub is a humanoid robot shaped as a four years old child. It is available as an open system platform following the GPL license. The iCub was originally designed by a consortium of 11 partners guided by the Italian Institute of Technology, with background ranging from engineering to neurophysiology and developmental psychology, within the RobotCub Integrated Project funded by European Commission through its Cognitive Systems and Robotics Unit. The iCub can crawl on all fours and sit up. Its hands allow dexterous manipulation and its head and eyes are fully articulated. It has visual, vestibular, auditory, and tactile sensory capabilities. In the past few years the community of researchers working on the iCub grew at a constant pace. Today there are more than 25 iCub platforms available worldwide. Simultaneously the platform evolved significantly in terms of its sensors and actuators. Thanks to the recent improvements the iCub is now equipped with: whole-body distributed tactile and force/torque sensing, series elastic actuators for compliant walking experiments (the COMAN actuators) and movable head with microphones, speaker, actuated eyes, eyelids and lips for speech and human-robot interaction studies. The key advantage of the iCub is that it is an integrated platform that allows the study of complex tasks that require speech and auditory perception, vision as well as proper coordination and integration of sensory data and control. We believe that this, more than ever, requires that researchers with different expertise join forces and start working together. Having platforms with compatible software and hardware is clearly a unique opportunity for collaboration.