The easiest major sight near San Pedro is the Valley of the Moon [Valle de la Luna] and its Great Sand Dune. Note walkers barely visible on the crest of the dune.
The Valley of the Moon [Valle de la Luna], part of the Cordillera de la Sal [Salt Mountain Chain] contains The Amphitheatre [pictured above, background], a salt-rock canyon, caves and some weirdly eroded shapes but the best sight of all is from or of the monstrous dune [above, foreground] at sunset. You will not be alone there, unfortunately, unless you're an early riser and choose to get there for sunrise instead.
The Valley of the Moon is about 14kms [9mls] from San Pedro and doable by mountain bike if you're fit.
