This haiku came to my mind when I was watching a TV document of a desert, where they found fossilized whale bones. That tells the area was under sea long long time ago.
The world is always changing. "Mujo" is a Buddhist term, meaning there is no usual. The changes, however, take place slowly, at least to our sense of time. It is like a bit of change a day, and accumulates day by day. This applies to our daily life, too. If one intends to bring about change, then one should start today.