Bangkok's family-run Wattana Panich restaurant has been cooking the same pot of beef noodle soup for a very long time. Forty-five years, to be exact.
Every day they simmer the stew — locally called "neua tune" — in that big pot, and every night they drain its broth to use in the next day's soup. You'll notice that the pot is encompassed by a dark residue, that's hardened soup that's been accumulating since the early seventies!
Great Big Story shares the tale of the 45-year-old broth:
"Fresh meat like raw sliced beef, tripe and other organs is added daily…. It's an ancient cooking method that gives the soup a unique flavor and aroma."