According to Michael Chaplan, you might not have to go far to find treasure:

“X” doesn’t always mark the spot when it comes to buried treasure. Often, treasure is hidden by landmarks such as stone walls or old outhouses, says Michael Chaplan, author of “The Urban Treasure Hunter: A Practical Handbook for Beginners”. Say you’re walking in the woods. “You look up on a hill and say, ‘Gee, maybe people had a picnic there.’ And you go up with a metal detector and find old coins,” he says.

A review of the book at Amazon by John Tabacco:
“Michael Chaplan’s personal treasure hunting motto is: “Anything can be anywhere.” And, he proves it time after time in his book with a fascinating array of treasure hunting adventures searching for and finding lost treasures in New York City. Treasure consisting of old coins, hidden caches, historical relics, antique bottles, precious jewelry, and prehistoric Indian artifacts.

His theory is that America’s urban areas have common treasure hunting zones, and that the rules for treasure hunting in New York City would apply to every other urban area. Of course this comes with some pretty unusual experiences. The chilling section where he’s drawn into the strange world of urban voodoo, after finding a ritual object, is one of the book’s many high points. As a writer, Michael Chaplan really has that special knack for bringing the reader along on his adventurous expeditions around town.

The Urban Treasure Hunter should be on every city dweller’s reading list. It clearly demonstrates that you don’t have to be in steamy far away places to find treasure, it’s right there in your own hometown. The book has a very attractive layout and is well illustrated with photos of interesting treasure finds, easy to understand diagrams, and useful charts. It’s also quite apparent that the author has thoroughly explored the intriguing history of New York, a once small seaport grown into a great city, and then a metal detector became his time machine. Highly recommended, even for armchair adventurers. An excellent read. Get ready to put on your Indiana Jones hat!”