Power returns to Sydney after three-hour blackout

The power is back on in Sydney, after a three-hour blackout caused chaos in Australia's largest city.

It’s thought that 70,000 homes and businesses were cut off during the evening rush hour.

Office workers were trapped in lifts, while the closure of the Sydney Harbor Tunnel created traffic gridlock.

The Sydney Opera House had to cancel evening performances.

Energy Australia says the power cut was caused by an unspecified problem with four large cables.