Acropolis of Athens, Athens

Buy the combined ticket online. You then just scan or show it at the entrance. Highly recommended! I didn't wait at all.. As for the Acropolis - it's definitely worth it, most impressive and interesting structure, however not my favourite of the top sites. It is great, no doubt, but the crowd is unimaginable, thus you can't really enjoy peaceful exploration. The top site can be explored in about an hour, HOWEVER (!!) be careful not to exit prematurely or you'll have to buy another ticket, depending on where you enter from. There are two entrances: on the top, and from the main street in front of the big glass museum. You should take the lower entrance and ask how to make your way up. I took the upper one, explored the Acropolis, exited, and was not allowed to go in from the other way. And I didn't see a way down through the Acropolis, but... oh well. The view is also good, the structure is in reconstruction, so the best thing about this part were the few statues.

It's the top place to visit in Greece and for a reason. All the history, the place itself, the constructions, the temples the theaters. Its absolutely a must do. Really enjoyed the view from the top. I would highly recommend to go early to beat the crowds. Its too many tourists and visitors. And it's worth it.