The Ethnographic Museum in Warsaw, Poland, was evacuated after workmen discovered an unexploded World War II-era mortar shell, police said. \"About 150 people were evacuated from the building,\" Warsaw Police press spokesman Sgt. Tomasz Oleszczuk said after the explosive was found Tuesday between the first and second floors of the building, which is being renovated, Polskie Radio reported Wednesday. Warsaw was the site of heavy shelling at the start of the war in September 1939, and the two-month 1944 Warsaw Uprising against Nazi German occupiers by Polish resistance fighters left much of the city in ruins.