Polonnaruwa was the island’s capital from the 10th to 13th century, and what remains is extraordinarily complete for its age. The Gal Vihara – where four Buddhas were carved from a single granite rock face – is the centrepiece. The Royal Palace ruins, the Sacred Quadrangle and the Vatadage are all within cycling distance of one another. Best with a specialist heritage guide who can make the medieval capital narratively alive.