Which sentence is written correctly?

The city, supposedly filled with gold, was a fable and the tired explorers would never find it.

The city, supposedly filled with gold, was a fable; and the tired explorers would never find it.

The city, supposedly filled with gold, was a fable, the hungry explorers would never find it.

The sentence that is written correctly is:

The city, supposedly filled with gold, was a fable; and the tired explorers would never find it.