It is a mystery to baffle the brightest gumshoe.
Why is this ash tree always festooned with footwear?
For almost 40 years, no one has been able to muddle out why people keep hanging shoes from the branches.
Some say that the culprits are preparing for an alien invasion - perhaps thinking the visitors might have packed too light.
Others believe that they are participating in a fertility ritual, hoping to double the number of pregnancies in the local towns and villages.
What is certain is that no one has admitted tying almost 100 boots, sneakers and high heels to the branches, ensuring that the mystery remains unsolved.
The ash growing by the side of the A 40 between High Wycombe and Stokenchurch in Buckinghamshire is the third tree to carry the shoes.
As the previous tree died or was culled, the shoes were moved on to a new ash.
David Holmes, 45, of High Wycombe, who regularly walks past the tree, said the area is still awash with rumours about its strange crop.
'There are so many stories about why the shoes appear in the branches,' he said.
'Some say it was a form of toll payment by travellers, or a fertility ritual, but I think it's probably a hoax that just carries on.
'Whatever the reason, new shoes keep appearing, even now.'
As the stories surrounding the attraction became part of folklore, the Special Trees and Woods project, part of a campaign to protect woods in the Chiltern area, added it to a list of 500 special trees.
In September 2005, the project was given £265,000 from the Heritage Lottery Fund and extra funding from local conservation groups to collect data and carry out research on special trees in the area.
Rachel Sanderson, co-ordinator of the project, described the tree as 'an absolute mystery'.
'When we heard about this tree, we realised that it had to be on our special tree list,' she said.
'We're here to use examples like this to try and leave a legacy which protects the local wildlife.'
In the past, lottery funding aroused stinging criticism for paying millions to bizarre causes.
These included a campaign to prevent the deportation of failed asylum seekers from Britain and a project to grow fatter guinea pigs for Peruvians to eat.
At the same time claims from the Samaritans have been turned down as have applications from rural communities because they do not have a big enough ethnic minority population.