United States
Beautiful lake right in the centre of Golden Gate Park. Hire a rowboat for about five bucks, and make nice lazy progress around the central island, perhaps stopping to pick blackberries on the way. Of all the things I did whilst in SF, this was the most relaxing and idyllic.
Muni (the municipal railway) offers connections to the park from transit stops throughout the city. See their pdf for more information: www.goldengateparkconcourse.org/docs/2005%20Muni_GoldenGatePark_Brochure.pdf
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