Natasha Belling

Musk and Altman helped start OpenAI together in 2015.

Under an agreement, it's alleged OpenAI would not be for profit, designing the technology for the benefit of all humanity.

The pair reportedly then had a falling out and a couple of years ago, Altman changed OpenAI into a full profit company, which is what Musk is suing over.

Opening arguments are expected on Tuesday, American time, and both Musk and Altman are expected to testify during the court proceedings.

And a dog has been rescued from the window ledge of a 13th floor apartment on Sydney's northern beaches.

LB, who is a Jack Russell, went missing over the weekend.

Her owner's putting out a call for help.

A neighbour came to the rescue and put up a drone which spotted the stranded pooch wedged in a narrow gap on the balcony.

After a delicate operation involving a number of firefighters and nervous onlookers, Elby was safely returned to her relieved owners.

Owner Alex Dobrin says he is incredibly relieved.

Elby was taken to the local vets to check she is all OK.

Now it's time to get into our deep dive on the Port Arthur massacre.

Today is the 30th anniversary of the horrid shooting attack that killed 35 people and injured many more.

Joining us to take us through the day that changed our nation forever is Seven News journalist Mike Amor.

Mike, thanks so much for joining us.

An incredibly difficult day for so many people, 30 years on from an event that certainly changed our nation and for the many, many victims and survivors that were involved in this tragedy.

And Mike, you were a journalist that was reporting there from that horrific scene, that massacre 30 years ago now.

Take us through what was happening when you arrived there because like so many people that were involved in this, everyone was in shock because they just couldn't believe what had unfolded.

Absolutely.

We know that Martin Bryant, and he was found guilty and is serving life behind bars right now, but we know Martin Bryant opened fire in that area at Port Arthur.