As the COVID-19 pandemic continues to spread more and more countries are going into lockdown and governments are urging citizens to practise social distancing - but this isn't the first time this has happened.
In 1918 an influenza strain known as the Spanish flu caused the worst pandemic in centuries.
It was thought to have begun in crowded army training camps during World War I where unsanitary conditions helped it incubate and then spread. When the war ended the soldiers returned home and brought it with them.
Between 50 and 100 million people are believed to have died.
In two months, New Zealand lost about half as many people to the Spanish flu as it did in the whole of the First World War.
In response to the outbreak, officials told Aucklanders to practice social distancing and enter self-isolation. Public events were cancelled.
In Christchurch movie theatres and schools were cancelled.
Wellington tried to keep up the appearance of normality and most businesses remained open.
New Zealand is now experiencing something similar over 100 years on from the Spanish flu, when on Wednesday, March 25 at 11:59pm the whole country entered a four-week lockdown to prevent the spread of COVID-19.
But while the Spanish flu was much more deadly, there are still some important notes we can take from the influenza.
Lockdown early
An American study into the influenza by H. Markel for the History of Medicine, University of Michigan Medical School found the most successful approaches to containing the influenza included early, sustained, and layered application of social distancing.
The BBC reported in Philadelphia, Pennsylvania during the early stages of the Spanish Influenza, the city's officials decided to go ahead with a local parade despite there being 600 soldiers infected with the virus. Meanwhile in Saint Louis, Missouri, they opted to cancel their parade and introduce other measures to contain the spread of the illness.
One month later more than 10,000 people had died of the Spanish flu in Philadelphia, but only 700 in Saint Louis. While the variables may not be the same, it does show the importance of going into isolation early.
The lockdown needs to be sustained
One of the main lessons we can learn from the Spanish flu is the importance of not giving up early.
The influenza took off in early 1918 in America but after months of isolation, business owners saw the trend in cases begin to decline and they decided to open their doors again.
Many people went back to work and officials resumed public events. Then the second wave hit, and it was more deadly than the first.
While New Zealand has currently imposed a lockdown period of one month, it will likely take much longer than that before the COVID-19 pandemic begins to slow.
The Director-General of the Ministry of Health says initial models show coronavirus cases here would peak in August 2020.
In the UK, Prime Minister Boris Johnson told Britons he planned to "send coronavirus packing" within 12 weeks and US President Donald Trump said he wants packed churches in as soon as two weeks and the US open by Easter.
The lockdown needs to be enforced
In 1918 people were familiar with the risks of not adhering to social distancing as diseases and pandemics were more common.
But because viruses aren't as common now, people may be less or more worried about what may happen if they don't adhere to the lockdown.
Experts believe social distancing won't be sustainable for weeks or months as people need to get out of the house and keep up social, physical and other activities and are more likely to break rules now to do so, Vox reported.
In his study, Markle said: "We're almost a victim of our own success. I'd rather be that way, frankly, because we have vaccines, antibiotics, and all these other things. But very few of us know about it."
Markle recommended that the lockdown was kept in place for as long as possible and was enforced strictly by the Government and police.
"Each [policy] is like a slice of Swiss cheese," Markel said. "You want to layer them over one another so the holes are smaller."
We are better equipped to handle viruses now
The health system is now better prepared to treat and manage pandemics than they were when the Spanish flu was around.
We now have antibiotics and vaccines which can help to prevent diseases which are much better developed now and researchers are already working to create a cure for COVID-19. Although there is currently no vaccine for COVID-19.
Markle said those most at risk from coronavirus including people with cancer, diabetes, heart conditions, etc are much better off now.
"These are people who would never be walking in 1918," Markel said. "They'd be dead".
