NPR's Ayesha Rascoe talks with travel writer and host Rick Steves about "overtourism" — when some locales prove too popular — and how not contribute to it. Summer travel season is ready to take off.

Pretty, pristine, and perched on a lake, with a striking mountain panorama as a backdrop, Luzern has long been Switzerland’s tourism capital. Since the Romantic era in the 19th century, it’s ...