A4

A4 and variants may refer to:

Science and mathematics

Medicine

Transportation

Aeronautics and astronautics

A4 autostrada (Poland)

The autostrada A4 in Poland is an east-west motorway that runs through southern Poland north of the Sudetes and Carpathian Mountains, from the Polish-German border at Zgorzelec-Görlitz (connecting to the German A4 autobahn), bypassing Wrocław, Opole, Gliwice, Katowice, Kraków, Tarnów, Dębica and Rzeszów to the Polish-Ukrainian border at Korczowa-Krakovets. The motorway is a part of the European route E40. As of October 30, 2014 about 628.45 km (390.50 mi) of the motorway have been completed, out of the planned total length of 672 km (418 mi). The final section east of Rzeszów is currently under construction and scheduled to open in 2016. The A4 parallels national road 94 (which connects with German Bundesstraße 6).

History of construction and plans for the future

Some western stretches of this motorway were initially built as a Reichsautobahn by Nazi Germany in the 1930s under her pre-war borders. After World War II and the takeover of Poland by the communist regime, with new borders, the existing roads received minimal maintenance and upgrades and became notorious for their poor quality, a phenomenon similar to that observed in East Germany. Extensive reconstruction, especially of the section between Legnica and Wrocław, has removed all traces of the old concrete road surface, but some aspects of 1930s standards of construction remain; for example, the aforementioned stretch does not have an emergency lane, a feature that is to be added in the future.

V-2 rocket

The V-2 (German: Vergeltungswaffe 2, "Retribution Weapon 2"), technical name Aggregat-4 (A-4), was the world's first long-rangeguided ballistic missile. The missile with a liquid-propellant rocket engine was developed during the Second World War in Germany as a "vengeance weapon", designed to attack Allied cities as retaliation for the Allied bombings against German cities. The V-2 rocket also became the first artificial object to cross the boundary of space with the vertical launch of V-177 on 20 June 1944.

Beginning in September 1944, over 3,000 V-2s were launched by the German Wehrmacht against Allied targets during the war, first London and later Antwerp and Liège. According to a 2011 BBC documentary, the attacks resulted in the deaths of an estimated 9,000 civilians and military personnel, while 12,000 forced laborers and concentration camp prisoners were killed producing the weapons.

As Germany collapsed, teams from the Allied forces—the U.S., Great Britain and the Soviet Union—raced to capture key German manufacturing sites, guided missiles, rockets and jet powered aircraft. Wernher von Braun and over 100 key V-2 personnel surrendered to the Americans. Through a lengthy sequence of events, a significant portion of the original V-2 team ended up working for the US Army at the Redstone Arsenal. The US also captured enough V-2 hardware to build approximately 80 of the missiles. The Soviets gained possession of the V-2 manufacturing facilities after the war and proceeded to re-establish V-2 production and move it to the Soviet Union.