On our second day in Vienna, my family decided on a whim to go up to Bratislava, Slovakia. It was the best idea, because (1) it was only an hour train ride away, (2) the old town is gorgeous and so worth seeing, and (3) the food was surprisingly good! We made sure to take plenty of photos while we were there, and enjoyed the sights and cool weather. Tristan enjoyed it the most, I think because he took the longest nap, ever (he was out for three hours, and I had to carry him the entire time).
If you have the time to make a side trip, I highly recommend going to Bratislava. It has a unique, old world feel that you wont find anywhere else. And if you can, order yourself a big slab of steak. We did, and it was one of the best meals we had during the trip. ❤