IMHO, the world's most obscure route operated by a widebody aircraft is Air India's service CCJ-AAN-SLL-CCJ operated by an Airbus 310-300.
I'm willing to bet that 99% of the world hasn't heard of even ONE of the cities served.
For the record it operates from Kozhikode, India to Al-Ain, UAE to Al-Salalah, Oman.