Short answers, pulled from the story.
Sevastopol was founded in June 1783 as a naval base by Rear Admiral Thomas MacKenzie, a native Scot in Russian service. Catherine the Great ordered Grigory Potyomkin to build a fortress there in February 1784 and formally name it Sevastopol.
Sevastopol is a compound of two Greek words: sebastós, meaning 'venerable,' and pólis, meaning 'city.' Sebastós was the traditional Greek equivalent of the Roman title Augustus, originally given to the first Roman emperor.
The siege of Sevastopol during World War II lasted 250 days. The city fell to Axis forces in July 1942 and was liberated by the Red Army on the 9th of May 1944, after which it was awarded the Hero City title.
The Schwerer Gustav was an 80-centimetre calibre railway artillery piece, the largest-calibre railway gun ever used in battle. German forces deployed it during the World War II siege of Sevastopol to destroy the city's heavy fortifications, including the Maxim Gorky Fortresses.
Russia annexed Sevastopol on the 18th of March 2014, following a disputed referendum on the 16th of March that official results claimed showed 95.6 percent support for joining Russia. The annexation is not internationally recognised; most countries continue to regard Sevastopol as part of Ukraine.
The Partition Treaty on the Status and Conditions of the Black Sea Fleet, signed on the 28th of May 1997, established the terms of Russia's lease of facilities in Sevastopol. A 2010 extension ratified by Ukraine by a 52 percent majority prolonged the lease through 2042 with options for five-year renewals.