On Tuesday, Irina Bokova, Director-General of the United Nations Educational, Scientific and Cultural Organization (UNESCO), urged Iraqis to safeguard that nation's trove of antiquities as assaults waged by the jihadist group Islamic State of Iraq and al-Sham (ISIS) have put relics there at risk for looting. UNESCO also has reported that in Egypt, terrorist attacks in recent years have targeted pieces of cultural heritage.
Antiquities plundering and trafficking is estimated to turn a $7 billion underground profit, according to Franscesco Bandarin, Assistant Director-General for Culture UNESCO. That's about one-tenth the size of global drug-smuggling operations, he added.
"People don't think this is a crime. They think this is a lesser crime," Bandarin said at a recent news conference. "That's why you find sometimes objects on sale even on the official auctions, which is quite a surprising thing."
Read MoreHow ISIS managed to acquire $2B in assets
Terrorists have long been tapping a chunk of the underground relic market. According to the FBI, "fundamentalist terrorist groups rely on looted antiquities as a major funding source."
In 1999, while seeking to raise money for the planned 9/11 attacks, one of the hijackers, Mohammed Atta, tried to sell a cache of pilfered Afghan artifacts in Germany, reports the FBI, based on accounts from the German secret service.
International laws, including a 1970 U.N. treaty, prohibit the illicit export, import and transfer of ownership of plundered cultural property. U.S. law incorporated that UNESCO treaty in 1983. Britain is one of more than 90 other countries to have signed it.
Read MoreIraq war: Here are the best and worst case scenarios
U.S. Homeland Security agents offer a running, online catalog of stolen relics that its agents have recovered and returned. Just from Iraq, those items include about 7,500 artifacts (several paintings plus a 4,514-year-old necklace that, after looting, had been sold at auction at Christie's in London).