These homeowners apparently have a fondness for the space program. They've found (or constructed) a whimsical rocket ornament and installed it on their lawn. Its size and uniqueness grants it immediate focal-point status.
Don't underestimate the importance of whimsey in landscape design. I find that the folks who derive the most enjoyment from their yards often have injected considerable whimsey into their landscapes. What else, after all, can lend a do-it-yourself landscape design as much authenticity as whimsey?
