!/16th inch steel cable is almost invisible, yet very strong. Get some 1/16 cable clamps to secure one end into a loop,put it around or through whatever you are attempting to keep in place.
Figure out what part of your display item is the thickest-strongest and loop through there,then drive a stake into the ground to secure the "Earth" end of the project.
Make sure to check with local utilities first and they have usually up to three days to arrive and spray paint lines to mark phone, gas, electrical buried services.
In Illinois its called "Julie" , I think ?