Please explain what "Dover Beach" is all about.

This poem begins as the speaker is looking out at Dover
Beach on the English coast at night with the moon in the sky. He calls his beloved to
the window to breathe the night air and to enjoy the view. He hears the endless roar of
the waves, which to him is a sound that makes him think of eternal sadness. This in turn
makes the speaker think that this was a sound that the ancient Greek dramatist,
Sophocles, heard long ago, which can be related to the ebb and flow of human misery. The
speaker then talks of the Sea of Faith, a very important metaphor in the poem, which,
once full like the tide, is now retreating. He implores his beloved to be true to one
another. Although the world in which they live may appear beautiful and fresh, it is
actually full of uncertainty and cruelty and pointless conflict. The only consolation
that can be found is in love.

It is important to remember
that this poem was written during the Victorian period of history, which was plagued by
doubts brought about by tremendous scientific advances and the difficulties that they
had reconciling those discoveries with traditional religious belief. This poem therefore
voices the fear of many that religion was going to be disproved by science, leaving the
world a very dark and terrifying place.