Name the song: "...I've travelled the world & the seven seas..."?

Questions

NetHack: Carrying this corpse protects you from being petrified by a cockatrice.?

NetHack: The genre of games which NetHack belongs to is called that.?

NetHack: This beast can help you identify your gems.?

New Orleans: "Laissez les bon temps rouler", one of N.O.'s mottos, means this.?

New Orleans: These buildings bordering Jackson Square are the oldest apt bldgs. in the US.?