1. Dallas Has An Underground Tunnel Labyrinth
Location: Texas's Dallas
Year Found: 1987 (Year Constructed)
Estimated Value: *Build Cost of $101.68 million
If you've seen Jordan Peele's film Us, you're probably aware of the reason this finding is rated as extremely spooky. The Dallas Pedestrian Network is a network of winding subterranean tunnels located in Dallas, Texas.

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Dallas Has An Underground Tunnel Labyrinth @bcshelby/Pinterest
Only those who are familiar with Dallas can navigate them, and they are difficult to locate. These tunnels, which connect some of Dallas' most significant structures, including apartment complexes, commercial buildings, and skyscrapers, are situated beneath the thriving downtown region of the Texan metropolis. When inflation is taken into account, the network's 1987 construction cost of around $39 million (or $101.68 million) was divided between the city and private businesses.
2.1 Coins from the 17th century Discovered in a Fruit Grove Could Answer a 300-Year-Old Pirate Mystery
Place: Rhode Island
Year of discovery: 2014
Value Estimate: $200–600 per coin*
Who doesn't enjoy a good pirate mystery? An Arabian coin from the 1600s was discovered in 2014 by a metal detectorist exploring an orchard in Rhode Island. Since the early European immigrants were not involved in commerce with Arab merchants, how did the coin get into the colonies?

300-year-old pirate mystery could be solved by 17th-century coins discovered in a fruit grove (@nydailynews/Pinterest).
The answer to this query helped to solve a centuries-old pirate riddle. The coin from Yemen, produced in 1693, may have belonged to the infamous pirate captain Henry Every. Before vanishing in 1696, it was believed that Every had traveled to New England, maybe to Rhode Island. This coin might have been part of Every's booty that he took, and he dropped it by accident while escaping the authorities hanging pirates. The enigma was further compounded when further coins were discovered in other New England states.
3. A 600-year-old Treasure Trove Discovered Under Norfolk Tudor House's Flooring
Location: Norfolk, England's Oxburgh Hall
Year Found: 2020
Estimated Value: Not Known
In 2020, while working diligently in Oxburgh Hall, a lone archaeologist discovered something extraordinary in the attic rooms. Under the Norfolk Tudor house's floorboards, Anna Forest unearthed the biggest treasure hoard ever found at a National Trust site.

600-year-old Treasure Found at Norfolk Tudor House Under Flooring @thetimessunday/Pinterest
Among the treasures was a book with blue and gold hues that appeared to have belonged to Oxburgh's builder, Sir Edmund Bedingfeld. Additional treasures were discovered scattered around the remainder of the land, including handwritten music from the 1500s, textile pieces from the 1500s and 1700s, and an opened box of chocolates from the Second World War. The building is still "giving up its secrets," according to officials, and fresh riches are being revealed "slowly."