In 1914, World War I began, the first scheduled commercial flight took place, Mother's Day became official and Babe Ruth made his Major League Baseball debut.Mobile users tap here to watch videoDuring that year of monumental events, Baltimore's Washington Monument became keeper of Baltimore secrets. On Wednesday, the treasures of a hidden time capsule were revealed. Since restoration work began at the monument in January, workers have found all kinds of things. But it was on Oct. 16 when the project manager made a big discovery."We found a lot of signatures and dates. There are signatures that we found in the basement from between 1819-1829. In a lot of the stones outside, we found craftsmen's names and dates, and just about three weeks ago, we found a commemorative date stone right from about 1820," said Dr. Lance Humphries, a member of the restoration committee.A time capsule was placed in the monument in 1915 as part of the centennial celebration. It was hidden behind a plaque for all those years."We hoped that there would be something back there, but we didn't think there would be. I removed the plaque just enough to stick the camera behind there to take a photo. When I realized what was on the photo, I put the plaque back and I called Dr. Humphries," said George Wilk, with Lewis Contractors.The copper box that was soldered shut appeared to be in good shape.Humphries described some of the items found inside the time capsule."The newspaper accounts do say there were souvenir programs from the centennial of the monument and some newspapers of the day, and we hope that there will be other things," he said.The capsule will be taken to the Walters Art Museum, where experts will determine when it will be opened.