The Lost City is a fictional location depicted in The ClueFinders 3rd Grade Adventures: The Mystery of Mathra. It is an ancient, abandoned city inside the Numerian rain forest.


The Lost City was originally inhabited by the ancient Numerians thousands of years ago. The city was said to have been very great, and was built by some of Numeria's greatest inventors. However, according to legend, the ancient Numerians were terrorized by a monster named Mathra. Eventually, the Numerians captured Mathra and locked him in a deep dungeon within the city, but they fled the city out of fear that Mathra might escape again. They locked the city gates with a golden key, which they split into two pieces and hid those pieces deep in puzzles in the Numerian rain forest. Once abandoned, the ancient Numerian city became known as the Lost City.

Locations Within the Lost CityEdit

In the GamesEdit

The ClueFinders 3rd Grade AdventuresEdit

The ClueFinders set out to find the Lost City after it appears that Joni's uncle Horace was kidnapped and taken there. LapTrap provides the ClueFinders with the location of the Lost City and the two keys to the city gate. After finding and entering the Lost City, the ClueFinders receive help from the city's guardians, so that they can thwart Fletcher Limburger's villainous plans.

Subject-wise, the Lost City contains all of the game's science and language arts activities.

The ClueFinders Real World Adventure KitEdit

The Lost City is briefly shown in a story that Joni tells, which is somewhat based on The ClueFinders 3rd Grade, but contains differences to the original events.