שולחן ערוך אורח חיים · סימן רכ״ח

English

Upon oceans, rivers, hills, mountains, and deserts one says, "Blessed are you, God our Lord, king of the world, creator of the original (first) creations." And upon the great ocean, and that is the ocean that is crossed to Israel and to Egypt one says, "Blessed are you, God our Lord, king of the world, creator of the great ocean."

English

Not on every river should you recite the blessing, but rather on the 4 rivers, as it is written "like Chidekel and Euphrates." And he who saw them in a place that wasn't normally walked by people.

English

And not on every hill and mountain should you recite the blessing, but rather only on hills and mountains that stand out as recognizably great and awe-inspiring.