Graham Hughes holds the Guinness World Record for being the "first person to visit every country in the world without flying." For his presentation video, Hughes filmed a one-second clip of himself in each of the countries. According to his YouTube video, the people in charge of validating records had to check "1,000,000 GPS data points, 10,000 photos, 400 hours of video, and 192 passport pages," a process that took an entire year.
Hughes' record is impressive, but it's worth mentioning that "every country" means every country recognized by the United Nations (there are a few that are not). Still, the video that the British filmmaker and super traveler shot along the way is awesome and trumps every collection of selfies you will ever take.