What can I see that came from previous Warcraft games?

"Warcraft III" introduced much of the history, or and lore, that became the foundation of "World of Warcraft." Here are some examples.

Cairne Bloodhoof, the tauren leader in World of Warcraft
©2004-2007 Blizzard Entertainment, Inc. All rights reserved. World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc. in the U.S. and/or other countries.
Cairne Bloodhoof is the leader of the Tauren people. He assisted Thrall in "Warcraft III" and established the city of Thunder Bluff after the game's conclusion.

Mannoroth s broken dagger in Ashenvale
©2004-2007 Blizzard Entertainment, Inc. All rights reserved. World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc. in the U.S. and/or other countries.
Grom Hellscream drank the blood of the demon Mannoroth, gaining power for the orcs but essentially making them Mannoroth's slaves. Grom eventually killed Mannoroth, freeing his people from the demon's curse and dying in the process. Mannoroth's weapon still hovers over Ashenvale, near a monument to the fallen orc.

A bell in the ruins of Lordaeron in World of Warcraft
©2004-2007 Blizzard Entertainment, Inc. All rights reserved. World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc. in the U.S. and/or other countries.
This bell tolled as Arthas slew his father, King Terenas Menethil. It now rests on the floor in the ruins of Lordaeron, which has become the gateway to the Undercity,
the undead capital city.

Sylvanas Windrunner, undead leader in World of Warcraft
©2004-2007 Blizzard Entertainment, Inc. All rights reserved. World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc. in the U.S. and/or other countries.
Sylvannas Windrunner, leader of the Undead, was once a high elf. Out of spite, Arthas resurrected her as a banshee.

Rexxar and Misha, Warcraft III characters who appear in World of Warcraaft
©2006 Blizzard Entertainment, Inc. All rights reserved. The Burning Crusade is a trademark, and World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc.
in the U.S. and/or other countries.
Rexxar and his companion Misha were the heroes of a "Warcraft III" bonus campaign. They helped Thrall build a new home in Durotar.

Maiev Shadowsong
©2006 Blizzard Entertainment, Inc. All rights reserved. The Burning Crusade is a trademark, and World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc.
in the U.S. and/or other countries.
Maiev Shadowsong was the jailor of Illidan Stormrage. She's now Illidan's prisoner in the Warden's Cage in
Shadowmoon Valley.

Next, we'll look at a few places that are new to the game rather than products of lore.