Sóstó (Salt Lake) is a small wetland nature reserve on the southern edge of the city, an easy fifteen-minute drive or local bus from the centre. The reserve protects a shallow lake and surrounding marsh that supports a good variety of waterbirds — herons, egrets, marsh harriers — and a boardwalk loop with a couple of hides lets you walk the perimeter.
It is a quiet, slightly scruffy local park rather than a polished tourist destination, and that is part of its appeal. The football stadium and a few sports fields sit at the northern end; the more interesting wetland is further south.