The Battle of Tobruk, or Siege of Tobruk, lasted for 241 days after Axis forces advanced through Cyrenaica from El Agheila in Operation Sonnenblume. The Allied occupation of Tobruk was crucial to deprive the Axis of a supply port closer to the Egypt–Libya border than Benghazi which was 900 kilometres (560 mi) west of the Egyptian frontier (and within the range of RAF bombers). For much of the siege, Tobruk was defended by the 9th Australian Division and other troops. General Archibald Wavell, the Commander-in-Chief of Middle East Command ordered Morshead to hold the fortress for eight weeks but the Australians held on for over five months, before being gradually withdrawn during September and replaced by the 70th Infantry Division, the Polish Carpathian Brigade and Czechoslovak 11th Infantry Battalion (East). The fresh defenders held Tobruk until they broke out on November 21 and held open an 8-mile (13 km) corridor, unsupported for several days, then captured Ed Duda on November 26, to link with the advancing Eighth Army, during Operation Crusader.
German submarine U-878 was attacked and sunk in the Bay of Biscay by British warships, HMS Vanquisher and HMS Tintagel Castle, using depth charges and squid mortar. The U-878 was sunk in position 47°35′N 10°33′W, all 51 crew members were killed.
Polish Air Force Tu-154 crash killed Polish President Lech Kaczyński and other dignitaries including the last President of Poland in Exile, Ryszard Kaczorowski. On 10 April 2010, a Tupolev Tu-154 aircraft of the Polish Air Force crashed near the city of Smolensk, Russia, killing all 96 people on board. \Other victims were the wife of the President, Mrs. Kaczynski, the chief of the Polish General Staff and other senior Polish military officers, the president of the National Bank of Poland, Polish Government officials, 18 members of the Polish Parliament, senior members of the Polish clergy and relatives of victims of the Katyn massacre. The group was arriving from Warsaw to attend an event marking the 70th anniversary of the massacre, which took place not far from Smolensk. The pilots were attempting to land at Smolensk North Airport – a former military airbase – in thick fog, with visibility reduced to about 500 metres (1,600 ft). The aircraft descended far below the normal approach path until it struck trees, rolled inverted and crashed into the ground, coming to rest in a wooded area a short distance from the runway. Various conspiracy theories about the crash have since been in circulation, and are promoted by senior political figures in Poland, who claim the crash was a political assassination.
Ryszard Kaczorowski was the last President of the Polish Government in Exile. He resigned his post following Poland's regaining independence from the Soviet sphere of influence and election of Lech Wałęsa as the first democratically elected president of Poland since World War II. He also passed the presidential insignia to Wałęsa, thus ending the 45-years long episode of the Polish government in exile. Kaczorowski was one of the victims killed in the plane crash which killed President Kaczynski along with many other dignitaries.