In the Victorian era they were strategically placed in the gardens so that the butlers could tend to guest's needs without staring directly at them. Homeowners could also see visitors approaching so they could magically appear to greet them.
Another practical use was to place one in the foyer to keep an eye on their daughter and her date as he bid her goodnight! Wow! Now that's what I call a security system!
Today they are mostly used for decorating purposes to add color and shape interest to gardens. Most globes range in size from two to 22 inches so making one to scale doesn't have to be exact.
I shoved the spike part down into a glue applicator tip, gave it a nice faux cement paint job and placed one of my dad's shooter marbles he had as a kid into it for the globe. I'm sure he won many games with it and what a proper way to show off his personal "Globe of Happiness!"