FAMILIES are being invited to enter a contest based on the life cycle of an oak tree.
The map-reading event, organised by the River Colne Project, is next Sunday.
The orienteering test starts from the Project's office at Slaithwaite Town Hall and is expected to take about 90 minutes.
The event is based on the evolution of an oak tree.
People will be given a map with 10 marked locations, each representing a point in an oak's development.
People must find the locations to reveal the sequence of the tree's evolution.
Mick Smith, River Colne Project officer, said: "This is by no means 100% accurate and is not meant to be taken fully seriously.
"But it is aimed at children and will hopefully give them an idea of what evolution means and get them out in the fresh air."
The event will start at 1pm.
For information, phone the River Colne Project team on 01484 847798.