Seville, the capital of Andalusia in the south of Spain, was the only large city captured by the Fascist rebels in the early days of the Spanish Civil War, and it served as their base of operations for the next three years. It was an unexpected victory; Seville was a stronghold of the republican* workers' organizations Unión General de Trabajadores and Confederación Nacional de Trabajo.
Note and caveat: the version of events I am relating here is what I got from Wyden's The Passionate War, backed up by some other 30-year-old books. Wikipædia says that while this narrative has attained mythic status, more recent research by Paul Preston contradicts it. I haven't read Preston's book yet but you probably should before you cite this account as authoritative or something.
General Gonzalo Queipo de Llano, the happy fellow to the left, had recently joined the Fascist conspiracy among high-ranking officers of the Spanish army, probably out of resentment at the way his friend Zamora, the former president, had been treated by the republican government. He arrived in Seville on July 17, 1936, with only a couple of people with him.
Went into the army headquarters, where nobody was because it was too hot, and took an office over for himself. Then he tracked down the division commander General Fernández Villa-Abrille, and demanded that he swear allegiance to the Fascist cause. Villa-Abrille refused -- not out of any principle but because he was worried the rebellion would be unsuccessful -- so Queipo de Llano arrested him and his staff. No locks were handy so he ordered them to stay in the room, and not come out or he'd shoot them.
Then he walked over to the infantry barracks (presumably leaving someone behind to guard the prisoners), walked up to the commander there, whom he did not know, and said: "I shake your hand, my dear Colonel, and congratulate you on your decision to put yourself on the side of your brothers-in-arms in these hours when the fate of our country is being decided." His chutzpah went unrewarded however; the colonel said he was supporting the government. Queipo de Llano arrested him, then one by one arrested other officers until he finally found somebody who would take command of the regiment under Fascist colors.They took the guns out into the central square of Seville and started shelling the Hotel Ingleterra, where the republican government officials were holed up. By the time the UGT and CNT got wind of what was happening and started resisting, governor Varela had already surrendered and the Fascists had taken over Radio Seville's transmitter, from where they were broadcasting notices that they were now in charge and everybody should take it easy and submit. The Fascists also took charge of the airport early on, and started getting reinforcements flown in from Morocco. In the meantime, Queipo de Llano had a couple of army trucks drive repeatedly down the main streets so it would look like there were a lot of soldiers ready to enforce.
The Passionate War by Peter Wyden, 1983.
The Spanish Civil War by Hugh Thomas, 1977.
The Revolution and the Civil War in Spain by Pierre Broué and Emile Témime, tr. Tony White, 1970.
A Concise History of the Spanish Civil War by Paul Preston, 1996
* (I know, weird: they were called "republican" but they wore white hats. Go figure.)