In the modern world, whenever something exciting happens, you can almost guarantee that we'll have photo and video evidence of it happening. Almost everybody has a smartphone, and so we have the means to record everything we see and hear on a regular basis. It's like we've all become photojournalists.
This hasn't always been the case. There are now more photos taken every day than there were in all of the 19th century. Some might say that we've become a little too trigger-happy and vain with the camera, but at least we never miss anything. We always capture the moment.
Because there were so few cameras around one hundred years ago or more, we have a literally incomplete picture of some truly remarkable historical events - the sorts of things there would be thousands of pictures of if they happened now. That doesn't mean there are no pictures at all, though!