A little less than 3920 km (or ~2435 mi). After this trip to Greece, my friends and I will be flying to Bologna, Italy, and road tripping through Florence and the five coastal cities of Cinque Terre! I will be traveling for a total of ten days before returning to Stockholm. This will add up to a grand total of almost 9,000 km (5590 mi) of traveling!
At the time of writing, I am sitting on the ground in the airport in Thessaloniki. So I have traveled a little less than 4,000 km.
I walked, took a train, took the commuter rail, took the bus, took a plane, and walked some more!
The most interesting place I visited would definitely would have to be the Acropolis and the Parthenon! There's something so different about being physically present, standing in front of an immense structure, knowing that it was built thousands of years ago. And then, when you start imagining how much work it took, and the intensive ingenuity that had to be utilized to complete the structures... it truly amazes me how resourceful and impressive these ancient civilizations were. I wish photos could capture these moments better, but I really just encourage you to go there directly yourself one day.