We caught a local bus from Potosi to Uyuni, a 7-hour slog across winding dirt switchbacks. I sat with Hey-There in the front, next to two very tall, very scrunched-up men from our group of nine.
Once, we were allowed off the bus to pee in the dirt behind a pig sty next to a restaurant. Though "restaurant" may be too broad a term to use for the concrete block alongside the road. We stopped other times to pick up passengers or let them off, and once for the bus crew to pick plants, but no other potty stops occurred. I'd been careful about my liquid intake being used to this sort of trip, but the plant-picking bit was as new to me as it was to the others in our small group.
Finally, we pulled into the dusty town of Uyuni, its frontier-feel obscuring the friendliness we'd encounter later when all of us went out for the best pizza in Bolivia, when I went to the market for a fresh juice, or when four of us went out in search of tough, plastic zippered bags. We were leaving all we could at the hotel during our 3-day excursion into the salt flats, and would substitute tough plastic for our regular luggage.
Photos of the bus journey are here.
And here is a little video for you.