By Sam Wilson, BBC News

媒體英語會帶大家一起學習 BBC 撰稿人在報道世界大事時常用到的單詞和短語。

Background: 十年前聯合國科教文組織(UNESCO)通過法案保護100年前的深海沉船。現存問題是是否應該保護那些歷史少于100年，而且有人不幸喪生的船只殘骸。

Polish authorities recently banned divers from coming within 500 metres of the Wilhelm Gustloff. The German ship was sunk by a Soviet submarine in the Baltic Sea in 1945. More than 9,000 lives are thought to have been lost - the single largest death toll at sea.

Last month, seven European naval associations condemned Dutch salvage firms which they said were desecrating sailors' graves. They'd been searching for scrap metal aboard three British warships torpedoed and sunk off the Netherlands in 1914.

UNESCO's Convention on the Protection of Underwater Cultural Heritage, which was adopted ten years ago, does not apply in these cases, because it only protects shipwrecks more than 100 years old.

Whether ships and their dead should be left to rest in peace, or are sites of legitimate archaeological interest, can be a vexed and often emotional question.

Archaeologists say their job is the recovery and meticulous preservation of priceless artefacts. Many of them reject the label "treasure hunters".

But, with deep-sea exploration equipment costing tens of thousands of dollars a day, they need to cover their costs somehow. It's no surprise, then, that a ship laden with gold, silver and other valuables is seen as the greatest prize.