WoW's 20th anniversary event will bring Blackrock Depths as a revamped raid, a return to the opening of Ahn'Qiraj, classic dungeon timewalking, and modernized Tier 2 transmogs

pcgamer.com:

While it causes me terrible psychic harm to admit, World of Warcraft is almost 20 years old. Earlier today, Blizzard released a video detailing its plans for WoW's 20th anniversary event, where it'll be bringing back classic dungeons, kicking off time-warping public events at the gates of Ahn'Qiraj, modernizing some of the finest armor sets of yesteryear, and generally making millions of Vanilla WoW players feel as though they're at risk of crumbling into dust.

First up on the festivities is the return of Blackrock Depths. The sprawling, multi-wing, subterranean dungeon was a beloved—or reviled, depending on who you ask—fixture of early WoW life, and it'll be returning for the 20th anniversary as a 10 to 15-player raid. It'll have eight revamped bosses and five minibosses, and will be runnable in LFR, Normal, and Heroic difficulties. If you've never been, expect lots of dwarves, elementals, and struggles with the map.

Next, we're headed back to the opening of the Gates of Ahn'Qiraj with the help of some bronze dragonflight time travel. Joining forces with Chromie, players will queue up to relive a major moment of WoW's history while battling some unexpected forces who've bled through from other points in the timeline, like the Legion, Kel'Thuzad, and more.

Continuing on our jaunt through WoW's past, we'll also see classic WoW dungeons join the rotation for Timewalking—a periodic in-game holiday where players can complete dungeons from previous expansions to earn current-day loot and cosmetics. Deadmines, Zul'Farrak, both Dire Maul wings, and both Stratholme wings—Rivendare's Charger is in the loot pool!—will be available in Classic Timewalking, which will join the ongoing Timewalking schedule after the 20th anniversary event. Timewalking is also getting a vendor refresh, meaning you'll have more cosmetics to spend all those Timewarped Badges on.

The yearly anniversary event is getting some changes, too. The attractions and activities are being moved to the entrance