Hornet nests hung on room balconies on consecutive floors of an apartment building in China.

The nests were found at an unoccupied structure in Xi County in Shaanxi province.

Onlooker Zhang said that the building was empty because it had just been completed and that nobody had been looking up at it recently because of a spate of heavy rains.

But once it stopped, they noticed the strange dome-shaped structures across five or six floors getting smaller as they went higher, with the way they were so regularly spaced making him wonder if they had been deliberately put there as a deterrent.

He said: "I was on my way to work when I saw the nests. They got successively smaller as they went higher, and I was joking that instead of installing anti-burglary devices, they had arranged for the insects to help them out".

Many Chinese high-rise homes are fitted with anti-theft nets that make it impossible for people to climb up from below in order to steal anything, and many said that this was a cheaper alternative.

Hornet nests hung on room balconies on consecutive floors of an apartment building in China.

The nests were found at an unoccupied structure in Xi County in Shaanxi province.

Onlooker Zhang said that the building was empty because it had just been completed and that nobody had been looking up at it recently because of a spate of heavy rains.

But once it stopped, they noticed the strange dome-shaped structures across five or six floors getting smaller as they went higher, with the way they were so regularly spaced making him wonder if they had been deliberately put there as a deterrent.

He said: 'I was on my way to work when I saw the nests. They got successively smaller as they went higher, and I was joking that instead of installing anti-burglary devices, they had arranged for the insects to help them out.'

Many Chinese high-rise homes are fitted with anti-theft nets that make it impossible for people to climb up from below in order to steal anything, and many said that this was a cheaper alternative.