Monaco

Monaco, officially known as the Principality of Monaco, is a sovereign city-state, country, and micro-state that is located on the French Riviera in Western Europe, about 15 kilometers (9.3 miles) from France's state border with Italy. In 2005, Monaco had an area of only 1.974 km2 (0.762 square miles), but now it has an area of 2.02 km2 (0.78 square miles), making it the world's second-smallest country, after the Vatican. Monaco's population as of 2018 was 38,682, with 19,009 inhabitants per square kilometer (49,230/square mile), and it is the most densely-populated sovereign state in the world. Monaco has a land border of 5.47 kilometers (3.40 miles), with the world's shortest coastline of approximately 3.83 kilometers (2.38 miles), a width that varies between 1,700 meters and 349 meters (5,577 feet and 1,145 feet), and through land reclamation, Monaco's land mass has expanded by twenty percent. Monaco is known to be the most expensive, as well as the wealthiest, place in the world due to its tax laws, since in 2014, it was noted that about thirty percent of Monaco's population was made up of millionaires.

Three Act Tragedy
After the funeral of his friend Reverend Babbington in Cornwall, Poirot travels to Monte Carlo in Monaco.