Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is the first movie made of Sir Arthur Conan Doyle's 1912 novel, which has been filmed several times since, and it's one of the first giant monster movies. Similar to King Kong (1933) they bring a dinosaur back to London which destroys part of the city. The dinosaurs are stop-motion special effects made by Willis O'Brien, who later worked on the original King Kong. They're not very convincing today, but in 1925 they probably thrilled the audience, especially the children. Despite the lack of sound and the primitive special effects, the movie is still fun to watch today. Like many silent movies of the time, the black-and-white film has been tinted different colors.
In the beginning we see Edward Malone, a young man whose girlfriend Gladys won't marry him because he's not a man of great deeds who has faced death. To impress her, Malone volunteers to go on an expedition to a dinosaur-populated plateau in the Amazon. The expedition party is made up of several other people including Paula White, the daughter of the man who originally discovered the dinosaurs, her pet monkey Jocko, and Zambo, a white actor in an unfortunate example of blacface makeup.
As the expedition members paddle two canoes on a small river on their way to the plateau, they pass a tree with a large boa constrictor wrapped around it. We see terrified looks from Paula and Jocko. Fortunately, the second canoe just paddles around the snake and nobody tries to shoot it.
Scenes like this, with a jungle expedition party passing a snake on a branch above them, show up frequently in adventure movies, and often someone shoots at the snake, but not this time. There are bigger and deadlier threats to shoot at to come.