Revelation 4:6
And before the throne there was a sea of glass like to crystal: and in the middle of the throne, and round about the throne, were four beasts full of eyes before and behind.
Nave's Topical Index—AKJV

Revelation 8:8,9
And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea: and the third part of the sea became blood;
Nave's Topical Index—AKJV

Revelation 10:2,5,6,8
And he had in his hand a little book open: and he set his right foot on the sea, and his left foot on the earth,
Nave's Topical Index—AKJV

Revelation 13:1
And I stood on the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and on his horns ten crowns, and on his heads the name of blasphemy.
Nave's Topical Index—AKJV

Revelation 15:2
And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God.
Nave's Topical Index—AKJV

Revelation 16:3
And the second angel poured out his vial on the sea; and it became as the blood of a dead man: and every living soul died in the sea.
Nave's Topical Index—AKJV

Revelation 21:1
And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.
Nave's Topical Index—AKJV