Far below the crowded sidewalks of 34th Street sits a veritable gold mine of treasure: hundreds of cellphones, iPads, laptops, bikes, backpacks, skateboards, clothes and even a three-foot tall karate tournament trophy.

These items, along with thousands of others, are awaiting return to their owners in New York City Transit's Lost Property Unit, a quiet, fluorescent-lit maze of shelves, drawers and lockers in the 34th St-Penn Station subway stop. Everything reported lost on a city subway or bus eventually ends up here. (Cash, however, is not kept at the unit.)

amNewYork recently toured the unit, along with the Metro-North Lost and Found, and saw a wall-to-wall library of commuters' forgotten miscellanea: Spongebob Squarepants backpacks, a motorized scooter, an electric popcorn popper, dozens of bags of luggage, boxes and boxes of glasses, an oversized pair of novelty boxing gloves and, curiously, a surprising amount of walkie talkies. The grand prize, however: During amNewYork's visit, a man picked up a voucher to retrieve $2,000 in case he had left behind in his travels.

(Wallets and cellphones are, unsurprisingly, the most commonly found items on subways and buses.)

So far this year, more than 16,600 items have been turned into the LPU, and about 5,800 of those have been claimed. Last year, a total 24,443 items came in, and 8,466 were claimed, or about 35%. For the Metro-North, more than 25,000 items were recovered in 2012, with about 13,000 being return. This year is tracking about the same numbers.

The intake at the LPU ebbs and flows by season, and right now the unit is in one of its busiest times of the year: kids are heading back to school.

"When the school year starts it's a really heavy period," said Bill Bonner, supervisor of the eight-person Lost Property Unit, addingthat winter and fall are typically the busiest seasons. "And this year we've had so many more tourists, we've seen a big increase in lost property coming in during tourism times."

Bonner added that the type of article coming in can vary with the time year: Around Christmas there are more shopping bags, summer sees more cameras and luggage from tourists, and so on. Summer also usually washes in at least one surfboard, but this year it never came.

Everything is typically kept for between 90 days and a year, depending on value, after which items are auctioned off in bulk on the MTA's website or, in the case of clothes and household pieces, donated.

Equally as wondrous is the Metro-North's Lost and Found, in Grand Central Terminal, housing all of the coats, strollers, umbrellas, pillows and more that are left behind in one of the eight stations this lost and found serves.

The Lost and Found is a cavernous room with white concrete walls and security cameras monitoring every square foot. Lording over the space is a 30-foot long elevated coat rack, where coats, jackets, suits and sportcoats of every style and type hang.

Everything here is kept for between 90 days and a year, after which everything is cleaned and donated. Like the NYCT's unit, phones, wallets and purses are the most common items, but it has its own collection of bizarre novelties: a music cymbal, a box of Legos, a guitar, a mic stand, aphotographic lighting shade, strollers, a Juicy Couture-encased iPad and, every once in a while, a "suitcase of adult toys," said Melissa Gissentanner, manager of the five-person Lost and Found.

"After a while nothing really surprises me," she said. "But every once in a while we'll get the item that makes you look at it and go, Huh."