One of the early Tarzan movies, made as a serial, was about a lost city. It was titled Tarzan and the Green Goddess and also as The New Adventures of Tarzan. One of the titles was used for a regular length movie edited from the serial. One unusual feature was that it was directed by Edgar Rice Burroughs' son-in-law, who also appeared in the movie. The plot involved a search for an idol (the Green Goddess) that contained the formula for a powerful explosive. There were multiple parties on the trail. It also featured lots of khaki, pith helmets, jungle scenery and all the other essential elements of adventure, even to include a tramp steamer. It was also unusual in that it was filmed on location in Guatemala in 1935. One character wears a pullover knit polo shirt, so it's okay for the rest of us to wear one, too, now that we know it's authentic adventure clothing. In the movie they had to trek through thick jungle to reach the lost city, as well as ride on a riverboat and on canoes. In reality, there really was a destroyed Spanish colonial city, as they described it, but it was actually in the center of a contemporary Guatemalan city, which I think was Antiqua. It was destroyed in an earthquake. Bruce Bennett played Tarzan in the movie and he lived to be 100.