A: 1919.

Q: Who was Horace Wells?

A: He was the first dentist to use nitrous oxide as an anesthetic. He experimented on himself in his office in December 1844, taking the gas and then having an upper wisdom tooth removed by a fellow dentist. Wells' office has since been replaced by the Corning Building, at the corner of Main and Asylum streets. Affixed to the base of the building - by the windows of a Burger King restaurant - is a plaque commemorating the experiment. (Some information taken from "The Miracle of Connecticut," by Ellsworth S. Grant.)

Q: Where is the "Behind the Rocks" neighborhood, and how did it get its name?

A: Behind Trinity College, beginning at Zion Street and extending westward to Brookside Street, with Flatbush Avenue serving as its spine. The college sits atop a high, rocky ledge, with the neighborhood below.

Q: What downtown street was notorious in the late 1800s as a "red-light" district?

A: Gold Street. At that time, it ran much closer to Center Church, at the corner of Main and Gold streets. But that still left room for a number of dilapidated buildings along Gold, where vice businesses flourished. A drive to clean up the neighborhood, led by philanthropist Emily Holcombe, led to the demolition by 1900 of the old buildings and a restoration of the nearby Ancient Burying Ground. In the mid-1960s, with the demolition of the Heublein Hotel and other buildings, Gold was realigned to angle away from the church and connect with Atheneum Square North, on the other side of Main Street. The "V" between the church and Gold now contains the once-controversial "rock sculptures." (Sources: "Images of America: Hartford," vols. 1 and 2, compiled by Wilson H. Faude.)

Q: Who was the first governor to occupy the Executive Residence on Prospect Avenue?

A: Gov. Raymond Baldwin. He moved into the mansion in 1945, two years after the state acquired it from the heirs of Dr. George C. F. Williams, president of the Capewell Horse Nail Company. The mansion was built for Williams in 1909, and he lived in it until 1933. He was an inventor who had found a better way to cold-roll steel to make horseshoe nails. His factory and wildly elaborate office building still stand, at the corner of Charter Oak Avenue and - how's this for a coincidence? - Governor Street. They are in very sad shape, however. (Sources: "The Connecticut Register and Manual" and "Structures and Styles: Guided Tours of Hartford Architecture," by Gregory E. Andrews and David F. Ransom.)