I'm not sure there's any one unique route, but the following seems a possibility - UK, Belgium, Germany, Austria, Hungary, Romania, Bulgaria, Turkey, Iran, Pakistan, India, Singapore, Indonesia, Australia. Another route would go more southerly, via France, Italy, Greece, Egypt, Saudi & Dubai. If you want to work the route out yourself, there's a rather small map at the following website -
http://www.mapsofworld.com/world-airroutes-map.htmr>(You could try asking an airline, but they might be reluctant to tell you these days!)