An aerial view of the Orkney Islands, Scotland May 3, 2014. During both World Wars, Scapa Flow was an important British naval base, and the site of significant loss of life. REUTERS/Nigel Roddis 

Divers prepare to dive on the wreck of a German WWI warship at Scapa Flow, Orkney Islands, Scotland May 5, 2014. Following the end of World War One, 74 German warships were interned there, and on June 21, 1919 most were deliberately sunk, or scuttled, at the orders of German Rear Admiral Ludwig Von Reuter, who mistakenly thought that the Armistice had broken down and wanted to prevent the British from using the ships. REUTERS/Nigel Roddis 

Skipper Angus Budge and his dog Hector take people out to dive on the wreck of a German WWI warship at Scapa Flow, Orkney Islands, Scotland May 7, 2014. Now Scapa Flow is a popular site for divers, who explore the few wrecks that still remain at the bottom. REUTERS/Nigel Roddis 

A dive plan of the Tabarka wreck is drawn on a dive boat at Scapa Flow in the Orkney Islands, Scotland May 6, 2014. The year 2014 marks the 100th anniversary of the start of the First World War. REUTERS/Nigel Roddis 

Ship's mascot Hector looks for divers returning from the wreck of a German WWI warship at Scapa Flow in the Orkney Islands, Scotland, May 7, 2014. REUTERS/Nigel Roddis 

A diver jumps into the water, ahead of a dive on the wreck of a German WWI warship at Scapa Flow in the Orkney Islands, Scotland May 7, 2014. REUTERS/Nigel Roddis 

A diver illuminates a gun on the deck of SMS Coln, a German WWI warship at Scapa Flow in the Orkney Islands, Scotland May 8, 2014. REUTERS/Nigel Roddis 

Divers explore inside the upturned blockship Tabarka in Burra Sound, in the Orkney Islands, Scotland May 8, 2014. Tabarka was deliberately sunk during WWII to try and block the path of German U-Boats. REUTERS/Nigel Roddis 

Divers explore inside the upturned blockship Tabarka in Burra Sound, in the Orkney Islands, Scotland May 8, 2014. REUTERS/Nigel Roddis 

A diver illuminates a gun on the deck of SMS Karlsruhe, a German WWI warship at Scapa Flow in the Orkney Islands, Scotland May 9, 2014. REUTERS/Nigel Roddis 

A diver swims past the boilers of the upturned blockship Tabarka in Burra Sound, in the Orkney Islands, Scotland May 8, 2014. REUTERS/Nigel Roddis 

A diver returns to a dive boat from the wreck of a German WWI warship at Scapa Flow in the Orkney Islands, Scotland May 5, 2014. REUTERS/Nigel Roddis 

Divers take a break after diving on the wreck of a German WWI warship at Scapa Flow in the Orkney Islands, Scotland May 5, 2014. REUTERS/Nigel Roddis 

A dive plan of SMS Kronprinz Wilhelm, a German WWI warship, is drawn on the window of a dive boat at Scapa Flow in the Orkney Islands, Scotland May 6, 2014. REUTERS/Nigel Roddis 

A dive boat moors up on the island of Hoy in Orkney, Scotland May 6, 2014. REUTERS/Nigel Roddis 

A memorial to Lord Kitchener, who died when the HMS Hampshire hit a German mine on June 5, 1916, is seen at Marwick Head on the Orkney Islands, Scotland May 3, 2014. Kitchener was on a diplomatic mission to Russia when the HMS Hampshire sank with the loss of over 600 lives. During both World Wars, Scapa Flow was an important British naval base, and the site of significant loss of life. Following the end of World War One, 74 German warships were interned there, and on June 21, 1919 most were deliberately sunk, or scuttled, at the orders of German Rear Admiral Ludwig Von Reuter, who mistakenly thought that the Armistice had broken down and wanted to prevent the British from using the ships. Now Scapa Flow is a popular site for divers, who explore the few wrecks that still remain at the bottom. The year 2014 marks the 100th anniversary of the start of the First World War. Picture taken May 3, 2014. REUTERS/Nigel Roddis (BRITAIN - Tags: CONFLICT ANNIVERSARY ENVIRONMENT SOCIETY MARITIME)

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A man takes a photograph of a blockship in the Orkney Islands, Scotland May 8, 2014. A blockship is a boat that has been sunk in order to block a waterway. During both World Wars, Scapa Flow was an important British naval base, and the site of significant loss of life. Following the end of World War One, 74 German warships were interned there, and on June 21, 1919 most were deliberately sunk, or scuttled, at the orders of German Rear Admiral Ludwig Von Reuter, who mistakenly thought that the Armistice had broken down and wanted to prevent the British from using the ships. Now Scapa Flow is a popular site for divers, who explore the few wrecks that still remain at the bottom. The year 2014 marks the 100th anniversary of the start of the First World War. Picture taken May 8, 2014. REUTERS/Nigel Roddis (BRITAIN - Tags: CONFLICT ANNIVERSARY ENVIRONMENT SOCIETY MARITIME)

ATTENTION EDITORS: PICTURE 02 OF 28 FOR PACKAGE 'WWI - EXPLORING SUNKEN WARSHIPS'
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Graves stand in Lyness Naval cemetery on the island of Hoy in the Orkney Islands, Scotland May 6, 2014. During both World Wars, Scapa Flow was an important British naval base, and the site of significant loss of life. Following the end of World War One, 74 German warships were interned there, and on June 21, 1919 most were deliberately sunk, or scuttled, at the orders of German Rear Admiral Ludwig Von Reuter, who mistakenly thought that the Armistice had broken down and wanted to prevent the British from using the ships. Now Scapa Flow is a popular site for divers, who explore the few wrecks that still remain at the bottom. The year 2014 marks the 100th anniversary of the start of the First World War. Picture taken May 6, 2014. REUTERS/Nigel Roddis (BRITAIN - Tags: CONFLICT ANNIVERSARY ENVIRONMENT SOCIETY MARITIME)

ATTENTION EDITORS: PICTURE 19 OF 28 FOR PACKAGE 'WWI - EXPLORING SUNKEN WARSHIPS'
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The graves of 13 German sailors who died in the Grand Scuttle stand in Lyness Naval cemetery on the Orkney Islands, Scotland May 6, 2014. During both World Wars, Scapa Flow was an important British naval base, and the site of significant loss of life. Following the end of World War One, 74 German warships were interned there, and on June 21, 1919 most were deliberately sunk, or scuttled, at the orders of German Rear Admiral Ludwig Von Reuter, who mistakenly thought that the Armistice had broken down and wanted to prevent the British from using the ships. Now Scapa Flow is a popular site for divers, who explore the few wrecks that still remain at the bottom. The year 2014 marks the 100th anniversary of the start of the First World War. Picture taken May 6, 2014. REUTERS/Nigel Roddis (BRITAIN - Tags: CONFLICT ANNIVERSARY ENVIRONMENT SOCIETY MARITIME)

ATTENTION EDITORS: PICTURE 18 OF 28 FOR PACKAGE 'WWI - EXPLORING SUNKEN WARSHIPS'
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A salvaged gun from SMS Bremse stands in the Lyness museum on the island of Hoy in the Orkney Islands, Scotland May 6, 2014. REUTERS/Nigel Roddis 

A poppy memorial for Leading Seaman Elias Dymock who died on HMS Vanguard, is seen on display at the Lyness museum on the island of Hoy in the Orkney Islands, Scotland May 6, 2014. On July 9, 1917, an accidental explosion destroyed HMS Vanguard, killing over 800 men. REUTERS/Nigel Roddis 

Gary Gibson whose mother, Peggy, witnessed the Grand Scuttle, sits at home in the Orkney Islands, Scotland May 5, 2014. Peggy and her sisters witnessed the Grand Scuttle in 1919 while they were on a school trip. REUTERS/Nigel Roddis 

The Italian chapel is seen on the Orkney Islands, Scotland May 8, 2014. During WWII, Italian prisoners of war were used to build what is know as the Churchill barriers, four stone causeways that link some the islands. REUTERS/Nigel Roddis 

The Italian chapel is seen on the Orkney Islands, Scotland May 8, 2014. REUTERS/Nigel Roddis 

The Italian chapel is seen on the Orkney Islands, Scotland May 8, 2014. An Italian prisoner Domenico Chiocchetti, built what is known as the Italian chapel at the prisoner of war camp. REUTERS/Nigel Roddis