A friend of mine from Australia is currently about three days into the newest ultra-endurance bike race – the Indian Pacific Wheel Race, 5,500 km of self-supported racing across Australia. Check it out here: https://www.indianpacificwheelrace.com/
Note that the leaders are averaging around 600km / day so far!
Indian Pacific Wheel Race
The #IPWR is a 5,500km (3,400mi) unsupported cycling race.
Starting in Fremantle, on the westcoast of Australia, it crosses the sparse Nullarbor plains, through to lush surrounds and urban scapes of Adelaide, on to Melbourne via the iconic Great Ocean rd and then on through the Australian Alps to finish at Sydney Opera House.