Qasr Farid in the south is the largest tomb of Madain Saleh and perhaps the most stunning, if not the most iconic in the region. Carved starting from the top – but never completed – from a free-standing rock monolith, its location gives it a rare beauty. Try to arrive as late in your visit (and as close to sunset) as you can, as the enigmatic tomb passes through shades of pink and gold until darkness falls: breathtaking.