Around 20 percent of this nation's landmass was recovered from the sea.  
Around 20 percent of this nation's landmass was recovered from the sea.  The highest point in this nation is 535 feet above sea level and located on the slope of Mont Agel, whose peak is in the territory of another country surrounding this one on three sides. This nation plays host to the only marathon whose course passes through three different sovereign nations, and one of the hardest Formula One Grands Prix. This nation ranges from 382 yards to two thirds of a mile wide. Its estimated thirty five thousand citizens cannot enter an edifice in its east hosting a casino.  For 10 points, name this second smallest sovereign nation located on the French Riviera which contains Monte Carlo.
Around 20 percent of this nation's landmass was recovered from the sea.  
Monaco