Pharrell Williams wrote 'Happy' for the 'Despicable Me 2' soundtrack, but it took an unconventional path to becoming a global hit. It was originally offered to CeeLo Green, who recorded a version that his label ultimately decided not to release. Pharrell's version eventually took off after the release of the world's first '24-hour music video,' a website that played the song on a loop featuring different people dancing in Los Angeles. The song hit number one in over 20 countries and became the best-selling song of 2014. Its success was driven by its relentless optimism and a neo-soul sound that appealed to all ages. The song inspired thousands of fan-made tribute videos from cities across the globe, making it one of the most significant cultural 'viral' moments of the 2010s. It won two Grammy Awards and was nominated for an Academy Award for Best Original Song.