Some of the most popular travel collectibles are also the most common. Take, for example, the seashell. Did you know that collecting seashells – the mainstay of travel collecting – is centuries old?

SARASOTA — Stuffed in drawers and gleaming on glass shelves, Tom Castle flashes a twinkle in his eye when he sees and talks about his seashell collection. It’s a “collector’s itch,” as he calls it, ...