I'd probably have to say one time I went to Spain, Paris and London, all in the same Summer. You see, I live in Mexico, but my maternal grandparents are Spanish, so we had the tradition to go to Spain in Summer almost every year. We don't do this anymore since my grandfather passed away two years ago, but I'm deviating from the subject. Being a child of divorced, it was a great pleasure when my father and grandmother came with us to Spain (my father and mother's dynamic is unlike any other divorcees' dynamic you'll ever see).
A few days after my First Communion, my dad kept saying that he was preparing my gift, which I had no idea what it was. One day, he told me to read a message on his cellphone. You can imagine my joy -I'm an Anglophile, by the way- when I read we were not only going to Disneyland in Paris but also to London, one of the places I longed to visit the most.
I had a great time in both. Ironically, it rained in Paris and was sunny all four days in London. Years later, I would find out that trip had an ulterior motive, which was to take me and my sister away for a while, since my grandfather was very ill and was even said he would die. Fortunately, he didn't.
I didn't know that at the time, of course; it would have probably spoiled the journey. But I firmly believe that was the best trip ever.