A pot of gold doesn't always sit at the end of a rainbow.

Instead, it can sit quietly in backyards, bathroom walls and even right beneath your feet. Some people set out to hunt for treasure, while others somehow manage to accidentally stumble onto valuable items.

We took a closer look at those who found fortunes unexpectedly, and discovered that many strange places have been home to some of the world's most expensive treasures.

Below, we've listed seven unusual places where people have uncovered hidden treasure.

1. $11 million worth of gold coins buried in a backyard

Last year, a California couple discovered a trove of gold coins in their backyard while walking their dog. Tucked away in eight buried cans were 1,427 rare mint-condition coins dating from 1847 to 1894. Don Kagin, a rare coin expert who represents the finders, appraised the U.S. coins at $11 million.

The couple, who want to remain anonymous, held onto a few of the coins and donated some of them to local charities before selling it on Amazon. Today, you can find some of the coins offered for sale by Kagin's on Amazon.com and on the Kagin's website.

2. $200,000 worth of coins in the wall of an abandoned home

Jeff Bidelman, owner of Rare Collectibles in Pennsylvania, was helping a family clean an abandoned home and appraising their furniture when he found approximately $200,000 worth of coins inside a wall.

Holding onto a bag of coins he collected from the house, Bidelman spotted a hole in the wall. The homeowner's daughter had mentioned that when she was a kid she would hear rumors of how people would throw money in there. Bidelman asked if he could tear it down.

"I kicked the heck out of it, ruined the front of my leather shoes and [coins] came pouring out," Bidelman tells Mashable.

So, where are the coins today? Bidelman last heard in 2010 that the coins were sitting in the homeowner's trust fund.

3. A valuable painting in a thrift store couch

In 2007, an unidentified German student got lucky when she purchased a secondhand couch for $215 at a flea market in Berlin. When she opened the pullout couch at home, she found an oil painting, 10 inches by 15 inches, that she eventually sold for a whopping $27,630 at a Hamburg art auction.

Although the artist's name is unknown, the work of art was said to be painted during the 17th century by someone who was close to the Venetian painter Carlo Saraceni. The name of the work is Preparation to Escape to Egypt.

4. $182,000 in Depression-era currency inside a bathroom wall

Bob Kitts, a remodeling contractor from Cleveland, Ohio, had torn down a bathroom wall, and found bills totaling up to $182,000. Inside the walls were white envelopes with a return address spelling out "P. Dunne News Agency." Apparently, a businessman named Patrick Dunne stashed the money inside the wall during the Depression era.

After discovering this, Kitts told the homeowner, Amanda Reece. Once the money was appraised, Kitts and Reece learned that the currency could be worth up to half a million dollars, since some of the bills were rare and collectible. Legal issues and arguments arose between Kitts, Reece and descendants of Patrick Dunne regarding who could keep what.

5. $426,856 worth of ancient coins in a field of barley

Martin Elliott was teaching his cousin Kevin Elliott how to use a metal detector at their family's farm in England when they discovered 9,213 ancient silver coins buried under soil. This discovery broke the record for the largest hoard of Roman silver denarius coins.

Most of the silver coins in the batch were common, but there were two unusual coins that had never been found before in Britain. In 2000, the coins were valued at approximately £265,000 ($426,856), and were purchased by Somerset County Council.

6. Declaration of Independence found in a flea market

In 1989, an anonymous man bought a $4 framed painting of a country scene at a Pennsylvania flea market. Little did he know, he ended up with one of the 24 known copies of the original 1776 Declaration of Independence.

In 1991, he sold the historical document at auction for $2.42 million. Nine years later, it was sold for $8.14 million to television producer Norman Lear.

7. $500,000 worth of coins in a storage unit

After bidding $1,100 on an abandoned storage unit, a man identified as John found hidden treasure estimated to be worth $500,000 in the unit.

Lying in the storage unit was a blue Rubbermaid container with rare coins and a few gold and silver bars. The auction was held by American Auctioneers, the company featured on A&E's popular television show Storage Wars. Unfortunately, cameras weren't rolling at the time of John's big win.