Ground-based observations of the long-term evolution and death of Saturn's 2010 Great White Spot

► We study in detail the evolution of the 2010 Great White Spot from December 2010 to September 2011. ► The GWS evolved into a planetary-scale disturbance in 50 days showing plenty of wavelike features. ► The GWS formed a unique long-lived large vortex (size ∼ 7000 km). ► The GWS head remained visible at optical wavelengths for 6.5 months. ► The zonal wind profile maintained its structure with maximum changes of 45 m s−1.