You relax on the banks of the river or the sea. Ask the child to build a sand castle. (However, this can be done and for the most ordinary sand heap.) The sand should be damp enough. Ask your child to build the Palace of Tsar Saltan, or the castle of Kashchey the Immortal. Teach him to do the tunnels and bridges. Decorate tower shells, and wall stones. Help your child if it does not work.
Take a picture of the architect next to his creation.
