Humans are curious by nature, actually all up-right walking primates tend to be curious, and that shouldn't surprise anyone. Nor should it surprise anyone to learn that any good book publisher that publishes nonfiction books will tell you that the word "secret" in the title of the book will help it sell more copies. There is something that is alluring to the fact that there is a secret, something we don't know about, that makes us all too curious to go and find out. Religions use this tactic to recruit individuals to their flock, and marketers use it to sell products and services.
Still, it's used so often, and there are so few secrets in the information age that the chances of you learning a real secret are slim to none. That is to say, sure you might learn something that you don't know, but it's hardly a secret. And there are many more information outlets to discover the exact same information, usually for free. It's even more so than it ever has been in the past because all of mankind's information and knowledge is now online on the Internet. With billions of people connected to this massive communication system the concept of keeping secrets will someday be a thing of the past.
What I am trying to say is the biggest secret of all; is that there really are no secrets, that is to say no important secrets. Yes there is undiscovered information, and there are some things that humans don't yet know about physics, but I guarantee you someday in the future our artificially intelligent supercomputers, along with our scientists will discover all that information as well. I'm sure you've heard the phrase; Unlocking the Secrets of the Universe. There are no secrets in physics - there are only challenges in the observational abilities, and the limits to the devices that we presently have to do the viewing.
There are no secrets to our world, no one is purposely trying to hide anything of any huge magnitude, just silly little things, that don't amount to a hill of beans anyway. Luckily humans are a curious bunch, and they were to seek out information they do not know. However, with over 7 billion people on the planet now - the chances of anyone secret escaping all of mankind in the past, present, and off into the future is highly unlikely.