In Sydney, the peripheral cliffs are abandoned, closed bunkers of the Second World War.
Nick Sais believes that this is the kind of sources that Australians should know about before the next disaster.
"Many people just ride past without being aware of what's at hand if they need it," says Sais.
"They are huge, they are absolutely huge," he says, showing the structures that look like hills, a few hundred meters across.
Mr. Sais runs the Australian Preppers Group. While preparing for a series of natural or human disasters, he believes that asteroids are the biggest threat.
"There are too many craters on Earth, too many craters on the Moon to say that this is impossible," he says.
"People are too crazy about what could happen."
It's not just about "preperate" or survivors who think they should be better prepared for the next disaster.
In recent years, several new research organizations have emerged that have studied what is known as the "existential risk" – the risk to humanity or life on Earth.
Many of them have published reports describing the likelihood and impact of major accidents, including the enormous effects of asteroids.
So how deadly can asteroids be?
Many asteroids hit the Earth with dramatic influences, including a rock that has erased many dinosaurs 65 million years ago.
It is likely that the asteroid, which created the 150 km wide Chicxulub crater along the coast of Mexico, would have a diameter of about 10 to 15 km.
Australia also carries scars of asteroid influences, some of which are larger than the Australian mainland, says astronomer Brad Tucker, who works at the Mt Stromlo Observatory at ANU.
Dr Tucker says that an asteroid that is large enough to create such a crater is catastrophic, and not just in the immediate vicinity where it hit.
When the asteroid hits the Earth's atmosphere, it explodes and releases huge amounts of energy.
In the 13 years between 2000 and 2013, the Global Nuclear Weapons Survey revealed 26 explosions of asteroids with more power than a nuclear bomb.
One of these was a meteor that exploded in 2013 over rural Russia.
It was only 20 meters across, but when it exploded about 20 km above the ground, it was briefly shining brighter than the Sun.
It smashed the glass, pulled people out of their feet, damaged thousands of buildings and caused more than 1,000 people to seek medical attention.
If the asteroid is larger than 20 m of the scale and actually touches the ground, the consequences can be even more dramatic.
"These things move so fast, with so much intensity as to literally cause the movement of the ground and the liquid," says dr. Tucker.
But all this liquefied, displaced land still tries to escape from the immense power that is released at the point of impact.
"Everything goes into the earth's atmosphere," says dr. Tucker.
"This powder layer will greatly extend the sunlight.
"Vegetation starts to die. Things that depend on vegetation disappear.
"It's not like all dinosaurs disappear at one time, it's a long period of global climate change, something we can not imagine that has literally changed the shape of the Earth."
Blind in the southern sky?
The Earth observation program uses a worldwide network for searching and tracking asteroids and comets.
But in 2013, their only observatory for tracking asteroids in the southern hemisphere – the Siding Spring Observatory in New South Wales was deployed.
Dr Tucker says that this decision left a gap in the size of the entire southern hemisphere in our tracking network.
"We are blind for 50 percent of the sky," he says.
In the same way we can observe the southern cross in the southern hemisphere, dr. Tucker says we'll only see a few asteroids under the equator.
Lindley Johnson, NASA's Planetary Defense Officer (yes, this is a real task), agrees that the loss of Siding Springs has left a gap in the Earth's network.
But, he says, we are not blind to objects that are approaching us from the southern hemisphere.
"It's true if your research goes just from the ground."
NASA also uses the NEOWISE space telescope to track asteroids coming from any part of the space, he says.
NEOWISE satellite has discovered around 33,000 objects near Earth in the last five years.
Mr Johnson also points out that his team now found that 90 percent of asteroids are 1 km across or more that are close to the Earth.
"It's estimated that the number of people is about a thousand," says Johnson.
"We currently have nearly 900 in our database.
"We still find one or two per year, and in fact we are doing an object that we believe the kilometer we have just discovered."
Nevertheless, there are still many smaller asteroids.
Mr Johnson has already described asteroids between 400 and 500 meters across the Earth as "climate change in the afternoon".
"The figures up to 100 meters are probably 25,000," says Johnson.
"So far, over the past 20 years, when we did that, we found about 8,000 of these people. About a third."
But, he admits, it will take until the end of the 2050s to find all these objects.
In order to help find the rest, new ground stations are being set up in South America and Australia.
"Both the space surveillance telescope that goes to Western Australia here, and then the Great Synoptic Transmission Telescope, which is being built in Chile, is expected to be operational by 2023," says Mr Johnson.
Until then, Dr. Tucker says we rely heavily on unpaid amateurs to help track asteroids in the southern hemisphere.
"It's literally the current state," he says.
One of these amateurs is John Broughton.
"Reedy Creek Observatory" in Gold Coast
Mr Broughton has outstanding results in astronomy: he noticed hundreds of near-Earth objects flying around our planet, including two comets.
He is so fruitful that he has his own Wikipedia page.
Mr Broughton works from his home on Gold Coast, using a telescope that he himself designed and built. His home is now internationally recognized as the "Reedy Creek Observatory".
"In 1997, I began to actively search for asteroids, and soon after that I found six new asteroids," he says.
Then in 2004 he noticed something strange on the telescope.
"[The object] it may have shifted 50 percent faster than a conventional asteroid, "recalls Mr. Broughton.
"At that time, I was not experienced enough to know that this is an indicator that this is an object close to the Earth."
This rock was more than a mile across, and because it came close to Earth's orbit, it was classified as a potentially dangerous asteroid or PHA.
This is almost the same as the 1998 Deep Impact movie began – young Elijah Wood sees his unusual object in his backyard, and the solitary astronomer confirms that the giant is asteroid, which is directed towards Earth.
In the film, an astronomer dies in a fiery car accident before he can notify the authorities.
Fortunately, in the case of Mr Broughton, he managed to inform the center for a smaller planet that catalogs all known objects near the Earth.
Other telescopes around the world were trained for PHA to better evaluate where it went.
While the discovery was rather "blown away", it is grateful that we were not all; Further observation confirmed that it will not hit the Earth.
But even if you could discover an asteroid that came to our path, could you do something?
Asteroid Reduction Plan
In the 1998 Armageddon movie on Asteroids, Harry Stamper, Bruce Willis left the mission to dismantle asteroid with a nuclear weapon.
In the real world, the task of our planetary defense officer, Mr. Johnson to discover the best way to stop the asteroid impact on the Earth.
"I want to tell people that I am Bruce Willis, but they are somehow laughing at me," says Mr Johnson.
But he is quite convinced that it is now possible to prevent an asteroid attack – albeit not in a Hollywood manner.
"This is one of the major natural disasters that can be prevented," says Johnson.
A Dual Asteroid Conversion Test (DART) is evidence of a concept mission scheduled between 2021 and 2022.
The plan is to launch a satellite on a small asteroid, which is currently in orbit around a larger asteroid.
"This is a very simple matter of transferring the movement of a spacecraft and its speed to the target," says Mr Johnson.
Even a small impact caused by a small satellite can push the object into space or move it from its existing orbit.
If the mission of DART is successful, it can be a plan to divert a larger asteroid, which will be directed towards the Earth in the future.
NASA also has other plans that they would like to test, including flying a satellite into orbit around the asteroid, slowly pulling it in one direction.
Explosions are not completely out of the list; Mr Johnson says that "removal" could also work on pushing the asteroid.
In this case, a laser or small explosion could trigger a stream of material from one side of the asteroid and push it from the direction.
"It creates a subtle jet thrust that again changes the speed of the asteroid, but it's enough," says Johnson.
Are the asteroids really the biggest threat to humanity?
But Mr Johnson believes that the Earth hit the asteroid is not a thing, but, but when.
Dr. Tucker agrees.
"Do I think we will see an event at the level of extinction in our life? No, no," says Dr. Tucker.
"Do I think that another Chelyabinsk will happen one, and people will see and feel the effects of this?
While the attack on the asteroid could cause a lot of damage, it may not be the greatest threat to humanity.
Human nature can be the worst enemy, says Johnson.
"At present, this is the only place we know in space – Earth – where we can live now."
Dr Tucker says that the problem is that we ignore the processes on Earth and in the universe that take place over longer periods of time.
"This is an equal treatment of the problem of climate change and" space things ".
"It's always a kind of laissez-faire type," this will happen in the future, we'll take care of it later, "but that's not the way to save it."
Back to Sydney, Mr. Sais plans in advance.
No one can say [a disaster] it can not happen here, "he says.