New York City-based lingerie brand Hanky Panky’s Valentine’s Day pop-up in Union Square.. Photo: Courtesy Hanky Panky Pop-ups aren’t new, but they’ve become even more popular since the early 2000s.

City kids need places to play outside, but too many neighborhoods don’t have access to parks or playgrounds. This is where pop-ups come into play. And if you’ve ever wanted to host your own, then keep ...