The Yucatán Peninsula is Mexico’s prime tourist hotspot, but most visitors stay in the north, around the “mega-resort” of Cancún and the stretch of Caribbean coast known as the Riviera Maya. The south of the peninsula is a different world, said Martin Symington in The Times – a vast, sparsely populated region which is relatively little visited by holidaymakers. The distances involved in exploring it are considerable (the Yucatán, which stretches…