Before rubbish collections, it was common to bury rubbish to dispose of it.

From bones to jewellery and bits of machinery, strange and unexpected things are lurking beneath suburban backyards.

Before regular rubbish collection was introduced it was common to dispose of things by burying them, but some finds still defy explanation.

In 2009 an entire rare 1920s motorcycle was unearthed in an Auckland veggie patch, while a Ferrari, a Daimler and a brand new plastic-wrapped SUV have been discovered in backyards overseas.

JASON OXENAM Karen Amor found this 1920s motorcycle buried in her backyard.

Some people have found fully stocked safe houses, tunnels and bunkers, while weapons and other military paraphernalia occasionally pop up too.

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In the 1970s, a human skull and shoulder blade was found under a house in Auckland, but were probably part of an old teaching collection.

Not so innocent was the skull found at beloved broadcaster David Attenborough's London home in 2010, later identified as remains of Julia Martha Thomas, a 55-year-old widow who was murdered and dismembered by her maid in 1879.

MARK CARWARDINE Used to discovering strange things in nature, David Attenborough's own backyard was home to a human skull left over from a grisly murder.

Suburban gardeners can expect long-gone cats or budgies to be buried somewhere on their section, but how about the Homed staffer's friends who unearthed an entire horse?

Buried in their Brisbane garden the family found the bones of the huge beast when they were excavating for a pool.

Other, much older, backyard bone finds include those from a mastodon from a backyard in Michigan dating back to the last ice age and the world's most complete snaggle-tooth shark skeleton in Maryland, thought to be about 15 million years old.

ISTOCK Bones of long-gone pets might be expected, but prehistoric sharks and fully stocked bunkers? Less so.

But its not all bones and scrap metal of course - in 2014 one lucky Californian couple unearthed an estimated $10 million worth of gold coins buried in cans on their property.

Have you found anything unusual buried in your backyard? Let us know in the comments below.