Wow - great question - it depends. There are memories of even so-so vacations that stand out.
One of the most beautiful places in the world is Lauterbrunnen/Grindelwald, Switzerland. My husband proposed to me on a hike we did there.
We also hiked half of the Tour du Mont Blanc - we hit all three countries. Coming from Switzerland into Italy and then up to the Refugio Bonnati was amazing - and the food at the huts - wow - especially in Italy.
We hiked the via Ferrata in the Dolomitis - you wear a harness and creep along cliffs hanging onto a cable - amazing views and mentally and physically challenging. Very relaxing for me as my mind tends to be cranking constantly - when you really have to focus, it can be mentally relaxing.
We just got back from Athens and loved the Temple of Poseidon - we managed to get there before it opened and had the ruin to ourselves - it was beautiful and amazing to be standing alone there with so much history. We also loved Santorini on one of our cruise stops - we hiked the atoll from Fira to Oia and when we got to Oia and sat down to eat we realized the post cards were not airbrushed!
We loved Algarve, Portugal - great food and wine. We also liked Andalucia, Spain. We walked through a Roman ruin of what was once a fish sauce factory - and then just outside was an amazing beach and restaurants with fresh grilled fish and vegetables and a nice crisp white wine. On that same Andalucian trip we visited the Alhambra and drove down through the original Sierra Madres - we stopped and bought some of the best olive oil I've ever had.
We hiked the Cinque Terre in Italy - gorgeous and yet again awesome food!
We liked Orvieto, Italy - a nice hill town just outside of Rome.
We loved Iceland - the free 'hot pots' - basically hot tubs filled with geothermally warmed water and dramatic scenery with volcanos and glaciers.
We liked Chile - the skiing and the Andes - plus the wine country.
Oh, and in Hawaii, we loved snorkeling in Shark's cove - I couldn't get my husband out of the water - he loved floating around looking at all of the really cool fish -that was amazing that in such a small area there were so many different fish and sea turtles - we loved it.
Alaska - we loved Sitka - there is a park there with the Totem poles near a stream - very nice.
Loved hiking Zion and Bryce - met mostly Europeans in the Bryce Canyon!!!
The most common element seems to be some physical effort (usually hiking) and mountains and then good food and wine. We've also had some awesome skiing experiences - being on top of a mountain again
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