I'll make mine a little more specific than 'African Safari' or 'Europe'...because as an avid photographer, I've thought about this for a very long time!
1. Mid-August, Mara River in the Masai-Mara of the Kenya/Tanzania border, at the narrows for the great wildebeest and zebra migration crossing. Tens of thousands of animals gather at the edge of the river, pumping themselves up for the necessary crossing to get to sources of water and grazing lands...while hundreds of massive crocodiles gather in the shallow waters to wait for the inevitable. It takes one brave soul among the wildebeests to jump into the water to start the avalanche of thousands of animals plunging in and swimming for the opposite bank, trying to avoid the massive jaws of the
crocs. Life and death and the full circle, played out each and every day of the migration.
2. Venice, Italy, 5am in early November. I'd wake while the city is still dark and asleep...listening to the echoes bouncing through the channels of the city workers and early fishermen getting their morning start, and watch the early morning mist and fog burn off in the first dawn light, revealing still-empty streets, night lights not yet turned off, golden sunlight with long shadows, and that gorgeous city all mine for that moment in time as the buildings glint out of the mist and the light fog casts gothic shadows and reaching fingers of sunlight.
3. Lukla, Nepal, late April-early May - Having flown in from Kathmandu to this small town, I'd embark on the arduous but gorgeous 7-day trek through Namche Bazaar and the river routes and past the monasteries, following the yak caravans up the Khumbu glacier to base camp with the season's climbers. Then I could photograph the great Mt. Everest from the Southeast route, and document the climbers through the icefall and up the Western Cwm and Lhotse face.
Those three would make me very happy!