When Franco launched his Aragon offensive in March 1938, the Republicans were exhausted and demoralized by the hugely bloody, but ultimately futile, defence of Teruel during the preceding winter. The Nationalists soon broke through, reaching the Mediterranean and splitting the Republican territories in two. The Republican counterattack overnight on 24–25 July took the Nationalists by surprise. Rapidly forming a bridgehead on the Ebro’s west bank, they advanced as far as Gandesa, but failed to take the town. Franco ordered dams on the Ebro to be opened, destroying the Republican bridges across the river, effectively trapping them in the bend they had captured. A brutal battle of attrition followed: the Nationalists had air superiority so could bomb with impunity. On 18 August, a dam opening again destroyed new Republican bridges. By the end of August, Republican annihilation was only averted by their heroically stubborn resistance and Franco’s hypercaution.
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