The salt flats, Salar de Uyuni, can be visited on daytrips, or longer trips, up to 4 days, including a swipe down towards the Chilean border and the lagoon and geysers of that area.
Make sure that you point out that you only wish to go with a responsible driver; there have been reports of drunkenness among drivers that may be averted with continued pressure on the tour companies before departure.
