For long time I had a crazy idea of making a functional lighthouse on my property. Initial idea was to just make a quirky lamp post for the overflow warning light of the septic tank, but since then it grew out to be its own sculpture.
I've made the top part out of 3d-printed parts and soldered brass wires and strips, with a cannibalized microwave motor that turns the lens (also 3d printed, but out of clear resin). It was intended to just be a decorative detail to add some life to the miniature, but later I discovered that the lens actually are functional, and properly focus the lightbulb's light!
The rest of the body was made with concrete over a plastic sewage pipe as base, reinforced with steel mesh for good measure. It was my first (and so far the only) time working with concrete, so I wanted this thing to be as durable as I could make it, just in case. Especially since it was intended to be a permanent oudoors installment.
I've painted it with white and light gray acrylic out of a shake can afterwards, and installed the top permanently. Plugged it into 220v light sensor that turns it on for a few hours after it gets dark enough. The final height of the whole lighthouse is ~1.5 meters. Biggest thing I've ever crafted! And fricking heavy, too, with all the concrete I think it weighs over 20 kg, I can barely lift it.
So far the thing ended up being impressively resilient, and it survived two winters now, one of which being really harsh and cold, with half-a-meter high snow cover. The only visible damage is that one of the railings de-soldered itself, but it is visible only on a close inspection.