What happens when wild chimpanzees go to a party? They wreck the furniture, wreak havoc, and make the whole house reek. To wreck is to ruin something, to wreak is to cause something to happen, and to reek is to smell bad.
A wreck is something that has been destroyed, like a car wreck or a ship wreck. If your room is a wreck, clean it up. Wreck is also a verb, so don’t wreck your bike by crashing into a tree. Here are some wrecks in the news:
It was the wreck that every wreck-finder wanted to find,’ says diver Richard Keen, who began searching in 1973 for Victory, the predecessor of Admiral Lord Nelson's more famous namesake ship. (BBC)

The storm has wrecked beach facilities, blocked roads and caused power cuts. (BBC)

Wreak (rhymes with “squeak”) means to cause something terrible to happen. It’s commonly used in the phrase “wreak havoc.” Pair wreak with abstract nouns, like "devastation" or "mayhem," rather than with physical objects. Here are some examples:

England has been hit by major travel disruption, flooding and power cuts as Storm Ciara wreaks havoc across the country. (BBC)

Many of the fires are small — but in a forest ill-equipped to withstand any flame, they can wreak devastating damage. (Washington Post)
Finally, to reek is to smell really bad, like an actual stinky smell, or to seem bad, like a stinky situation. Rotting food in the fridge reeks, and if the boss hires her son, that reeks of nepotism. Observe:
The streets reeked of overflowing garbage; residents told me the government had barred municipal workers from collecting it. (New York Times)

Clubs could rebuild with honor, dignity, and integrity, instead of enacting shady teardown schemes that reek of deceitfulness. (Washington Times)
If you get them mixed up, just remember, wreck has a “c” for “crash,” wreak has an “a” to match the "a" in the “havoc” that it causes, and reek starts with an “r” like “rancid” and “rotten.”