Recently I received a catalogue for expensive small-group holidays in interesting places. My eye was caught by The mysteries of Persia, taking in Isfahan, Shiraz, and Persepolis. In fact, I have been to those places: I toured Isfahan in a guided small group, and went to Persepolis with just a car and driver. In addition, I have hiked in the Elburz mountains, skimmed stones on the Caspian Sea at twilight as the terns dived and the night fishermen were setting out, and visited the Shah's Palace and the Carpet Museum in Tehran. All this for far less than the advertised cost of the holiday in the brochure! Mathematics is the most universal subject; there is not a country in the world with no mathematicians, and if you have something to say to them, they will accept you as one of them and show you the best their country has to offer. The generosity and friendship I have met among mathematicians in many parts of the world is indescribable. I have taken some remarkable train journeys (through the Rocky Mountains from Vancouver to Calgary; through the Tejo gorge in Portugal; on a remarkable feat of Victorian engineering from Mumbai to Pune; down the east coast of Queensland; and across both islands of New Zealand); have taken part in a tea ceremony in Tokyo, stayed in a farmhouse near the Douro, run round the lake under the mountains in Bled, walked across the Banks Peninsula and in Banff national park, watched Kathakali dance in Kochi and heard and spoken to the great Indian violinist V. G. Jog in Kolkata, seen Nilgiri tahr in Eravikulam national park and alligators in the Everglades, cruised the Bosphorus at dusk, and bathed naked in hot spring water in Hakone. None of this would have happened if I had not become a mathematician!