August is prime travel season in Europe- especially for Europeans. It is also smoking hot in most of the major cities making most outdoor activities uncomfortable. If you go, I'd suggest somewhere like Chamonix, France up high in the Alps or maybe the Swiss Alps since you would have a bit cooler temperatures and beautiful views and hikes up there. If at all possible I would suggest waiting until September for Europe. I never had luck nonreving to Europe in the summer, but I did have quite a few nice trips there in the Spring and Fall. Mexico and the islands would be a lot easier to visit since they are more off season now- I did Cancun one July and it was pretty easy to get there and the all-inclusives were pretty cheap. They are probably even cheaper now. Good luck wherever you go.