The path to enlightenment lies behind one of two doors. In front of each door stands a guard who knows which door leads to enlightenment, but one of the guards always lies and the other one always tells the truth. In your search for enlightenment, you are allowed to ask one guard only one question that can be answered “yes” or “no”, but unfortunately, you do not know which guard is the liar. You will be banished to the dungeon of logical illiteracy if you fail in your quest. What question should you ask to find the path to enlightenment?

New Orelans was founded in 1718, over 290 years ago. Hurricane Katrina brought flooding and devastation to New Orleans in 2005. The levees separating Lake Pontchartrain and Lake Borgne from New Orleans have been repaired, but the city remains at risk because many areas are at or below sea-level. Taking into consideration that global warming is melting the Arctic ice, how likely is it that New Orleans will still be inhabitable in the year 2100?