Victoria's government has been catapulted into crisis mode with an upsurge in coronavirus cases in recent days.
As an outsider looking in, the situation begs the questions: what went wrong, and how can we stop infection rates spiking elsewhere in Australia?
Here's a breakdown of where the pandemic is at in Victoria, what is being done to tackle the state's increase in COVID-19 cases, and what the situation means for the rest of the country.
Why is Victoria seeing such an increase in COVID-19 cases when other places aren't?
The jury is still out on why COVID-19 cases have increased significantly in Victoria rather than in other places, but the state's health minister on Friday flagged it could be because of a "super spreader".
Jenny Mikakos told reporters: "There seems to be a single source of infection for many of the cases that have gone across the northern and western suburbs of Melbourne.
"It appears to be even potentially a super spreader that has caused this upsurge in cases."
Last Tuesday, genomic sequencing revealed that a big proportion of Victoria's new coronavirus cases were related to infection protocols being breached in hotels hosting returned travellers.
But Victoria's Deputy Chief Health Officer Annaliese van Diemen said the super spreader theory was not the only one being investigated by authorities as the possible cause of the upsurge in cases.
She said a single very infectious person could have visited multiple locations and sparked the outbreak in Victoria, or alternatively there could have been multiple introductions from overseas.
"We don't have a single super spreader per se, but it is one of the epidemiological theories that is being looked at by our team of very experienced epidemiologists who are trying to work through the data that we're getting," Dr van Diemen said.
A total of 74 new coronavirus cases had been recorded in Victoria over Saturday night, bringing the state's active caseload to 543 people by lunchtime on Sunday.
Of those 74 new cases, authorities traced 16 people's infections to known outbreaks. State Premier Daniel Andrews on Sunday said one person was a returned traveller in hotel quarantine, four had their infections detected through routine testing, and the source of the remaining 53 cases was under investigation.
Does the situation in Victoria amount to a second wave of coronavirus?
No. Deputy Chief Medical Officer Professor Michael Kidd told media as much on June 28. He described the situation in Victoria as an outbreak and said while the term second wave was not well-defined, it could be likened to what was seen during the Spanish flu pandemic.
"[That] was a wave which went right across the world with further very high rates of infection, and very high rates of mortality occurring and, of course, that's not what we are seeing at this time," he said.
But authorities have warned Victoria's upsurge in coronavirus cases could escalate into a second wave if residents don't abide by the rules. Premier Mr Andrews on Sunday said no one would be spared the cost of a second wave; the situation was serious, real, and everyone had a part to play.
"We're trying to contain [the situation], bring some stability, and then drive down case numbers and get back in control of this across the board," Mr Andrews said.
"We need everybody to follow the rules and use common sense, and fundamentally understand this: no one will be spared the cost of a second wave.
"It will affect everyone ... so, no matter what your motivation - whether it be civic duty, or your high regard for your next-door neighbour or others you've never met, or just your own interests - everyone should be motivated by doing the right thing because everybody will pay a price if we can't get it back to a sustainable level."
Why has the Victorian government implemented Australia's first hard lockdown?
As of Sunday, there were stay-at-home orders in place for 12 Melbourne postcodes. Residents in these areas could leave their houses to go to work or study, provide care or get medical treatment, buy food and essentials or get exercise.
But some 3000 residents in nine public housing towers in Melbourne's inner north were told they were not allowed to leave their homes at all. On Sunday, Mr Andrews said this measure was put in place for protection, not punishment.
Police were stationed at the towers to ensure residents complied with the hard lockdown - the first of its kind in Australia during the coronavirus pandemic.
"This is not going to be a pleasant experience for those residents but I have a message for those residents: this is not about punishment but protection," Mr Andrews said.
"Because of the vulnerability of people in these towers, a hard lockdown like in aged care was deemed appropriate and, again, there will be mixed views about whether that was the right way to go, but that is the public health advice and we are well served by following public health advice."
The decision to impose a hard lockdown on the towers' residents has been controversial, with concerns raised by the social service sector that any mistakes in the management of the lockdown could prove "horrific".
But Mr Andrews attempted to quell some fears on Sunday by announcing that the about 3000 residents would have their rent waived for the next fortnight and receive hardship payments. The government would arrange the delivery of food and medical supplies to all tower residents, and mental health support and other services would also be provided.
"We will get to every single person what they need," Mr Andrews said.
How have border restrictions changed for travellers?
As of Sunday, there were still no restrictions on leaving or entering Victoria. That didn't apply to people living in Melbourne's locked-down postcodes or towers, though, because interstate travel was not one of the reasons they could leave their homes.
Queensland's borders are reopening to all interstate travellers except for Victorians on July 10, and anyone entering the Northern Territory who has visited a coronavirus hotspot has to self-isolate for two weeks.
Victorians as well as people from NSW and the ACT have to quarantine on arrival in South Australia.