This is the first film of Sir Arthur Conan Doyle's tale and significant for two reasons.
First, Sir Arthur Conan Doyle appears in the film and, since he died five years after it was released, it may be the only chance you have to see the creator of Sherlock Holmes.
Secondly, it was the first significant use of stop-motion animation in a major motion picture. The Allosaurus (I was really surprised they didn't use T-Rex), and the brontosaurus and the other dinosaurs were three-dimensional and really seemed alive. Amazing for 1925.
Sure, it is a silent film, but it had a King Kong/Jurassic Park story that was fascinating. They actually brought a brontosaurus back to London. It went swimming down the Thames at the end and I imagine is currently seen in Loch Ness.
The film features Oscar Nominee Bessie Love; Oscar nominee Lewis Stone, who was nominated in an Oscar winning film, The Patriot, which has been lost; Oscar winner Wallace Beery (The Champ, The Big House); and professional wrestler Bull Montana as an ape man.
A true classic!