With President Donald Trump in the White House, Mexicans are once again fond of quoting an aphorism coined by their late writer Porfirio Diaz : "Poor Mexico, so far from God, so close to the United States."

Mexico City's Zocalo or main square is one of the most historic places on the planet, with ancient Spanish churches built on even more ancient Aztec ruins; the colonisers forced the locals to destroy their pyramidal temples and build churches out of the stone.