Weird, like beauty, really is in the eye of the beholder. What's weird or strange to one person may be perfectly normal to the next. With that in mind, here are among the 10 weirdest things to happen in Pittsburgh.

1. A plane disappears in the Mon.

Perhaps one of Pittsburgh's greatest unsolved mysteries began on January 31, 1956 when an Air Force B-25 plane en route to Harrisburg radioed to make an emergency landing at Allegheny County Airport. Instead, the plane landed in the Monongahela River but claimed the lives of two of the five men on board. The plane sank in 20 feet of water - and still hasn't been found.

2. Earthquake!

An earthquake in Pittsburgh? Stranger things have happened, right? Well, maybe not. Back in 2011, an 5.8 magnitude earthquake struck below the ground in Richmond, Virginia. Not too long afterward, Pittsburghers felt the earth move beneath them. But, that earthquake didn't top the one in 1998 when a 5.2 magnitude earth quake, with an epicenter in Jamestown, rocked Western Pennsylvania.

3. A giant duck comes to town.

How many of us were among the tens of thousands of Pittsburghers who swarmed the river's edge on September 27, 2013, in eager anticipation of the city's newest and largest visitor: The Giant Rubber Duck? That adorable duck, 40 feet tall, docked in Pittsburgh, drawing countless visitors who wanted to snag a selfie with the famous waterfowl.

4. Cars roll uphill.

Something weird happens to cars that stop on McKinney Road in Allison Park: They roll (or appear to roll) backwards uphill. While some claim that the vehicle rolling uphill is an optical illusion, others swear that it's an authentic natural phenomenon. Discover this natural phenomenon at 601 McKinney Road, Allison Park 15101.

5. A UFO (allegedly) crashes.

A UFO allegedly crashed in Kecksburg way back in December of 1965. See the sight where the UFO is said to have landed. At its spot sits a giant acorn - yes, acorn - designed by Unsolved Mysteries in 1990. The popular TV show came to town to film the story of the UFO. The acorn was the replica the show designed and, after filming, it was forgotten. In 2006, the town decided to prominently display the Space Acorn and it's been a must-see attraction ever since. Visit the Kecksburg Space Acorn at 5123 Water Street, Kecksburg.

6. Two men steal a bridge (yes, a bridge!).

Covert's Crossing Bridge in Lawrence County won the starring role in countless haunted tales. But, that's not what's weird about the bridge. What's really weird about Covert's Crossing Bridge is two brothers dismantled it - all 31,000 pounds of steel - and sold it for a measly $5,200. (The steel was worth $100,000.) Both men were arrested for their antics.

7. A dead man is reappointed to office.

Larry Markwood earned the honor of being reappointed to Fayette County's Industrial Board in 2015. He would never attend any meetings during his reappointment because, unbeknownst to the board who green lighted the reappointment, he had died in 2012.

8. Mysterious tiles appear.

The Toynbee Tiles started mysteriously appearing in cities across the United States in the 1980s and kept popping up through the turn of the century. Six such tiles appeared in Pittsburgh, all bearing a message similar to "2001 Resurrect Dead on Planet Jupiter." Two of those tiles have been paved over while four remain in the city, including on Forbes Avenue and on Smithfield Street.

9. Steelers + Eagles = Steagles?

Once upon a time - back in 1943 - the Pittsburgh Steelers and Philadelphia Eagles intense rivalry was turned on its head when the two teams merged to become the Steagles. Many players on both teams went off to fight in World War II, making the merge necessary. Surprisingly, the team tallied a record of five wins, four losses, and one tie.

10. Some claim Jack the Ripper is from...Pittsburgh?

Who was Jack the Ripper? From where did he come? If you ask some people, you might be surprised to hear Pittsburgh and the suspect's name was Francis Tumblety, a New York man who was in London when the murders occured. A Pittsburgh handwriting expert - based on a comparison of writing samples from both Tumblety and Jack the Ripper - concluded the two men were the same.

What are the weirdest things to happen in Pittsburgh during your lifetime so far? Going along with the theme of weird, check out the 10 weirdest places you can possibly go around Pittsburgh.