Blurred Lines — Robin Thicke ft. T.I. & Pharrell (2013)

The biggest-selling single of 2013, this Marvin Gaye-indebted groove spent 12 consecutive weeks at No. 1 in the UK and sold 5.5 million copies in its first year. Its controversial video and lyrics sparked a global conversation about consent and representation, making it a cultural flashpoint unlike any other track here. Faster than the average pop hit, the song's infectious bassline and Pharrell's falsetto hook propelled it to become the second-best-selling digital single of 2013, trailing only Adele's "Skyfall" in the UK.