With a bucket and a dream, this artist creates truly one-of-a-kind sandcastles.

Artist Calvin Seibert battles time and nature in his work every day. Ultimately, every day, he loses.

Seibert spends his summers building sandcastles.

Modern, stunning, mind-melting sandcastles.

And as impressive and inventive as each one is, they all eventually go right back where they came from.

But it doesn't stop Calvin from dreaming and building all over again.

Like most kids, Seibert grew up playing in the dirt.

A child of the 1960s, Seibert could often be found goofing off and playing with his brothers and friends on construction sites near his childhood home in Colorado. The boys would play in the sand and watch the city grow up around them.

"You'd find all of this junk material to drag home and build a tree house with," Seibert recalls. "And they had piles of sand because they used to mix concrete on site."

While most kids trade in their sandbox for more traditional pursuits, Calvin leaned in. When he moved to New York in 1979 to attend art school, he started making sandcastles on the beach.

Now a freelance artist's assistant, Calvin spends his summer days building modern, stunning sandcastles.

His flexible schedule allows him to spend as many summer days as possible building jaw-dropping structures out of sand.

Each one is inventive, ornate, and meticulous.

He draws his inspiration from the brutalist architecture movement popular in his youth.

The style features defiant, expressive concrete buildings and structures, and it's easy to see the influence in Seibert's work.

"The whole reason I make the sandcastles so smooth and hard-edged is really coming out of ... seeing those buildings and being excited by that."

Most of Seibert's castles have striking smooth lines and curves, almost appearing to come from a mold.

But in reality, it's just Seibert's hands, his homemade plastic sand tools, and a five-gallon bucket he uses to dig holes and carry water.

It's physical work, and Seibert certainly gets his exercise in carrying up to 250 gallons of seawater to each structure. That's part of what makes each build so precious; it's only a matter of time before the physical stress may prevent Seibert from doing what he loves.

"It's hard work," Seibert says. "If I waited 10 or 15 years to do it in retirement or something, I wouldn't be able to do it ... I better do it now, time is ticking away."

But for now, the work keeps him young. That and a well-oiled imagination.

"Every day, I try to make something different," Seibert says. "I try to up the ante, add something new, and find something new, and things reveal themselves. I find myself doing something I hadn't expected."

Each castle takes less than a day to build and often just minutes to destroy.

Seibert works quickly, sometimes attracting an audience of kids and adults mesmerized by what he can do so quickly with organic materials. He works without a plan, letting the sand, surf, and love affair with architecture inspire him. Some days it comes easy, others, not so much.

"Nature will always be against you and time is always running out," he wrote on his Flickr page. "Having to think fast and to bring it all together in the end is what I like about it."

Once his sandcastles are built, seabirds, ocean waves, curious kids, and beachgoers have their way with them. But Seibert doesn't see it as a loss; it's simply part of what makes his work so beautiful and life-affirming.

Nothing is permanent.

Not the sand hills of his youth, the shores he builds on today, the castles he dreams up, or the knees and arms he relies on to get the job done.  But it doesn't stop Seibert from pushing himself to create the impossible and sharing it far and wide.

"It's the nature of the thing," he says. "You move on and make something new," he says.

It's true of sandcastles, art, and life: While you're here, use your gifts to make as much beauty as you can and share it with the world.