Mukalla, Yemen - From mid-July to early August each year, the coasts of the Yemeni city of Mukalla and neighbouring regions experience a natural phenomenon in which the hot and humid temperature drops and the sea's tidal waves turn chilly.
The cold spell, known as "upwelling", occurs as currents cause hot, surface waters to sink and cold, deep waters to surface, helping to cool Mukalla's sweltering summer.
Until 2011, when Arab Spring protests swept through Yemen, local authorities had arranged an annual festival to take advantage of the phenomenon to boost tourism in Mukalla - but it was put on hold as violence spiralled out of control. The situation in Mukalla was exacerbated last year, when al-Qaeda seized the city.
But this year, with al-Qaeda now cleared from Mukalla, local authorities opted to revive the tourism festival for two weeks late last month. Turnout was high, as people flocked to the coastline for a brief respite from Yemen's war.