The answer for the riddle 1:
The Frog Pond

1 Frog pond

Boston Common was once scattered with small ponds, and the Charles River ran much closer to this park than it does now.

One American author wrote at 1910 about French sailors celebrating the surrender of Cornwallis during the Revolutionary War: “Here, in the Frog Pond, the local tradition insisted that the common sailors of the fleet proved themselves true Frenchmen by hunting for frogs.”

Still, the pond’s use during the early 1800s was more for slaking the thirst of cows, and there was even a movement to change the name to the gentler Crescent Pond.

Frog Pond was gradually converted to a manmade pool starting in the mid-1800s, when water from Natick’s Lake Cochituate was first channeled into its towering fountain.

And now this multi-purpose pond serves as an outdoor ice-skating rink in the winter and as wading pool for youngsters with a 70-foot spray plume in the summer.