The tradition and trends, not to mention the fashion and fascinators. It's no secret that the British love their hats.
"I love seeing the colors…and the different materials…and how well they wear it," Tina Kite, a milliner based in metro-Atlanta, said of the upcoming royal festivities.
Kite, who started creating hats in 2002, knows the influence a royal wedding brings to the millinery business.
"People are thinking about hats…for the wedding it's required for women to wear a hat," Kite said.
Hats with a crown, typically created by hand using a hat block, are one option you'll see for Prince Harry and Meghan Markle's nuptials. Also popular among royals? The fascinator, an ornate headpiece decorated with flowers or feathers, which can range from small and elegant to edgy.
"People are inspired by something more interesting…a little crazier and wild and eccentric which I love," Kite said.
So who are the must-know milliners whose designs you're likely to see at the royal wedding?
"The big ones in London are Philip Treacy and Stephen Jones," Kite said, adding those are just a few of the notable milliners on the London scene.
So the golden question - does the dress come first or the hat?
"I always say pick your hat and then find an outfit to wear with it," Kite said. "The occasion is made even more special by wearing a hat."