From fossilised iguanas to Obama's head, conspiracy theorists appear to have found all manner of things on Mars.

And now an alien coffin can be added to the list, after one Maryland-based UFO hunter spotted what he believes to be a 'decorative' box on the red planet.

The 'coffin' was discovered by Will Farrar from WhatsUpintheSky37 as he trawled through a library of pictures sent back by the Mars rover Curiosity.

'This little box sure does look like a modern coffin concrete liner,' he wrote on his YouTube channel.

'As well as the stonework on the back part of the hill that looks like stairs or some left over stonework from some old civilisations constructions.'

More than likely just a basaltic column. To read more, click here.