With more than 300 ponds on Cape Cod, choosing a mere 10 is a thankless task. Finding them can be even trickier. Unlike bay and ocean beaches, where signs point you in the right direction, towns on the Cape like to keep these warm freshwater locales a secret. Many of these ponds have limited resident-only (with requisite sticker) parking. Fortunately, they are near town centers, so you can grab a bike and go have a dip.