Sunscreen is possibly the most often repeated - and ignored - piece of skincare advice.
But Thomas Leveritt took a different tactic. With a short film posted to YouTube that's been viewed more than 12 million times as of Saturday, Leveritt showed people what they look like under ultraviolet light, the damaging spectrum of sunlight, revealing unseen damage beneath their skin.
Then he showed them something even more remarkable: how sunscreen works. People with darker skin have more melanin, which gives skin its pigment and helps it become more resistant to sunlight (which doesn't mean they don't need to wear sunscreen). It's also produced by the body when exposed to sun, creating suntans. Sunscreen forms a barrier on the skin, making it appear much darker and harder to penetrate for sunlight.
A sunscreen should be broad spectrum, meaning it protects from UVA (the ones that give you premature wrinkles) and UVB (the ones that cause sunburns) rays, and at minimum SPF 15. Check out our guide to avoiding skin cancer for more sun-related tips.
So even when it's cloudy, even during winter, even on your ears and other often-forgotten areas, follow Baz Luhrmann's advice and wear sunscreen.