27th May 1915
Western Front
French take Les Quatre Bouquetaux (near Souchez).
Severe fighting in Bois-le-Pretre.
Eastern Front
Russians take Sieniawa (north-west of Jaroslau) and Kindowary (Shavli district).
Southern Front
Italians occupy Grado and Ala (Trentino).
Aviation
French airplanes bomb factories at Ludwigshafen, Germany in one of the first strategic bombardments in history. 203 bombs of a new type weighing 100 kg (220 pounds) are used.
Naval and Overseas Operations
H.M.S. "Majestic" torpedoed off Gallipoli.
HMS Princess Irene explodes in the Medway Estuary due to a faulty primer on a mine. 352 people are killed.
Political, etc.
Admiral Sir H. Jackson appointed First Sea Lord.
Portugal: President Arriaga resigns.
King Victor Emmanuel of Italy heads to the frontlines as Italy begins advancing into Austria-Hungary.
Ship Losses:
Cadeby ( United Kingdom): The cargo ship was shelled and sunk in the Atlantic Ocean 20 nautical miles (37 km) south west by south of the Wolf Rock, Ireland (49°40′N 6°10′W) by
SM U-41 ( Kaiserliche Marine). Her crew survived.
HMS Majestic ( Royal Navy): Naval operations in the Dardanelles Campaign: The Majestic-class battleship was torpedoed and sunk by
SM U-21 ( Kaiserliche Marine) in the Dardanelles and sank with the loss of 49 of her 672 crew.
HMS Princess Irene ( Royal Navy): The minelayer, a converted ocean liner, exploded and sank in the River Medway off Sheerness, Kent with the loss of 350 lives.
HMT Rolulu ( Royal Navy): The naval trawler was wrecked on the Obb Rock, Isle of Lewis, Outer Hebrides.