A city on the north Adriatic coast of Croatia, on the tip of the Istrian peninsula. The native (Croatian) spelling is Pula, Pola is Italian. The city has about 50K residents. They mostly live of services, mainly tourism - the city's ancient coliseum and basilica are quite some attractions, since they are from the Roman period and yet fairly well preserved. Also notable is the shipbuilding industry ("Viktor Lenac" shipyard).
It was the main naval base of the Austro-Hungarian Monarchy until the monarchy fell apart. And now for a tangential historical note -- at the end of the WWI, Austro-Hungary was in ruins and the issue of the navy needed to be resolved quickly. The Austrians didn't want their fleet to fall prey to Italy, so they handed it over to the newly made Slavic state on October 31st, 1918. This happened in the Pula harbor, on the warship called Viribus Unitis. Two saboteurs sunk the ship the morning after. They were from (you guessed it) the Italian navy. Four days later, the Italian troops entered Pula.
Also, "pola" is the word for "half" in Croatian.