There's a cross in the dirt and the dirt is surrounded by flowers and shells from shellfish. This is a tomb. The flowers and shellfish were put here as decorations and to honor the dead that currently lay under the dirt. And the cross marks the tomb, obviously.
This may be a tomb, but it feels really fun (ふん). It is decorated, after all. This tomb isn't a sad place, it's a fun place to remember the people you loved.