Sigiriya or Pidurangala - which rock should I climb?

Climb both if you can. Sigiriya (USD 30 entry) is the UNESCO-listed rock fortress with frescoes, water gardens and Lion's Paw entrance - historically and visually unmatched. Pidurangala (USD 3 entry) is the neighbouring rock; the summit gives the best view of Sigiriya itself, especially at sunrise. Do Pidurangala at 5 am, then Sigiriya from 10 am when the tour groups have left.