* Astronomy

The Battle of Messines was a battle of the western front of the First World War. It began on 7 June 1917 when the British Second Army under the command of General Herbert Plumer launched an offensive near the village of Mesen (Messines) in West Flanders, Belgium.
Co-ordinated by the Corps of Royal Engineers tunnelling companies, over a period beginning more than a year before the attack, Canadian, Australian, New Zealand and British engineers tunnelled under the German trenches and laid 22 mines totalling 455 tonnes of ammonal explosive.
The largest of the 22 Messines mines was at Spanbroekmolen; the "Lone Tree Crater" formed by the blast was approximately 80 m in diameter, and 12 m deep. The mine consisted of 41 tons of ammonal explosive, located in a chamber dug 27 m below ground.
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