Sandcastles are great! They are fun and relaxing to build. They bring out your creativity. A sandcastle doesn't have to be perfect, either, because the tide will soon wash it away.
Some people like building sandcastles so much that they don't stop when summer vacation is over. These are the people who become sandcastle pros. They build huge sandcastles in malls and for special events. They enter big-money sandcastle competitions.
These professionally built sandcastles can weigh many tons. Sometimes, they're not even castles at all. Sand sculptors have built dragons, dolphins, and mermaids, too. They have built all kinds of real and imaginary creatures. One group of sculptors built a pirate ship. Another group built a cow playing the violin.
They don't call it building, though; they call it carving.