Andorra, Liechtenstein, Monaco, and San Marino qualify as microstates, and each is nestled in a different part of Europe. The total population of the four slightly exceeds 150,000, and Andorra accounts for almost 69,000. Their geographic sizes are also small: Andorra occupies 464 square kilometers (179 square miles); Liechtenstein, 160 square kilometers (62 square miles); San Marino, 61 square kilometers (24 square miles); and Monaco, only 1.95 square kilometers (0.75 square miles). What is remarkable about the four is that each has managed to retain its sovereignty and its national character, despite being squeezed by larger neighbors. Andorra is a wedge of land between Spain and France, San Marino is surrounded by Italy, Monaco is located near the southeastern part of France, and Liechtenstein sits between Switzerland and Austria.

(MAP BY MARYLAND CARTOGRAPHICS/THE GALE GROUP)

Monaco is the smallest of the four, but is larger than the Vatican. Now a constitutional monarchy, it has been...