What are some secrets or lesser known facts about our world that you cannot research or learn about on the Internet?

Nothing really. Reality is overrated. To defend my answer here are things you can do online today: Communicate with anyone, anywhere using voice, pictures, text and audio. Build and foster relationships with people, even to the point of falling in love. Learn how to perform any task from changing a lightbulb to how to escalate to sexual intimacy on a first date. Share anything you wish with anyone you wish including what you see from your own POV. I am beginning to see that the Internet will actually one day be where some people enjoy spending most of their free time, as an alternate to our physical reality instead of just as a complement. They will still need to eat and use the bathroom, but there is no reason these experiences will not become integrated into the 'Internet of things' as just another layer of metadata for us to manipulate. Games like Second Life demonstrated that people will accept virtual reality even to the exclusion of physical reality if it serves enough of their needs. In trying to answer this question, I was first focused on thinking of things that you could not possibly learn or research through the Internet and I was quite befuddled when the realization dawned upon me that even human interaction with a human teacher or lover is possible through the Internet. True, e-learning and teledildonics are not yet mainstream, but they will be one day.

I agree with Paulo's answer. He gives a very good example of the Sistine Chapel. Let me however, share with you some of of my own experiences. I moved to the US some years ago and with the relative ease of movement here, I try and get out as much as I can. There are 2 incidences of my travels that I would like to share with you. A trip to Niagara and another one to the Grand Canyon. Both times, I was reluctant to go. Niagara has been photographed so many times from so many angles that I ended up believing it was right in my backyard. When I was in Toronto, with a busy schedule and all, it had even crossed my mind to skip Niagara. Fortunately, a relative insisted that we go. When there, I was blown away. The roar of the falls, the awesomeness of the whole spectacle and to feel the spray of the water stinging against my face is a memory to be cherished. Of course I took the obligatory pictures and showed them to my family who hadn't been there. I saw the same "yeah right" look that would have been on mine before I had been there. Same with the Grand Canyon, no doubt there are beautiful pictures of the Canyon on the internet and videos as well. I spent 3 days there and over that time, I saw a different version of the GC every time. Apparently, the scenery totally changes with the amount of natural light and the season as well as the climate (something no doubt, photographers and video directors have already realized).On my first day, it was raining, the next it was sunny. There are just no words to describe the experience. Did I forget to tell you that I have seen pictures and videos of Niagara and the GC from when I was 10. I got to actually see them 20 years later and I will definitely go back because I am in awe of what I experienced when I was there. That is hopefully once I get to see other great and beautiful landscapes and cities as well. March on!

If I can't write about it how can I answer it here in writing. But I guess I can take the stance that words can point to things not contained in words, that we can say 'look there.'   There is very little being censored on the Internet.  And frankly when a group moves against any knowledge being posted not he Internet I would become suspect.  The web has captured pretty much a reference to all major systems of knowledge and experience. That said its pretty easy to slip beyond the realms of language and global communications and touch things that can not be discussed. For example no one can tell you how it feels to be in love. No one can tell you how it feels to be proud of an accomplishment. Though there is a lot of information about Zen and Buddhism on the web, it is not the same as going into a Zen centre and learning to meditate for yourself. Though you can read about the world no one can tell you what will happen to you if you travel around it. In fact each moment of your life reveals something you can never see before and will never see again. Go on to a bus, before you get on you can have no idea where you will find a seat, who will be sitting next to you, what the people on the bus will look like, what they will be doing, how it will smell, what you will be thinning and feeling, what you will remember. The great unknown is not hidden on some mountain top monastery somewhere where monks levitate or in some unknown language on some stone wall somewhere, the unknown is what will happen after the next breath....