Revelation is the last book in the Bible - it is full of prophecies and end time events including armageddon
1:18 I [am] he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and of death.
(11) And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
(12) And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is [the book] of life: and the dead were judged out of those things which were written in the books, according to their works.
(13) And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
(14) And death and hell were cast into the lake of fire. This is the second death. [this is not annihilation]
(15) And whosoever was not found written in the book of life was cast into the lake of fire.
The Lake of Fire and Hell
From the readings above it can be seen that HELL is the place where the damned go before judgement day and THE LAKE OF FIRE is the place they go after judgement day. The Lake of Fire is therefore Eternal Hell as Hell is cast into the lake of fire which is eternal - so also is the suffering of those who are thrown into the lake of fire. The following quotes explain this more...
Revelation 20:10 says that "...the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet [are], and shall be tormented day and night for ever and ever." The wicked are tormented for ever. Revelation 14:10 - 11 says that the devil and all the wicked "...shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb: And the smoke of their torment ascendeth up for ever and ever."