While it depends on exactly what kind of "extremes" you're referring to, Venus is often considered the planet with the most extreme conditions overall.

Here's why:

* Hottest Surface Temperature: Venus has a scorching surface temperature of around 867°F (464°C), hot enough to melt lead. This is due to a runaway greenhouse effect caused by its dense atmosphere of carbon dioxide.

* Highest Atmospheric Pressure: Venus's atmosphere is 90 times denser than Earth's, equivalent to being 900 meters (3,000 feet) below the surface of Earth's oceans.

* Slowest Rotation: Venus rotates incredibly slowly, taking 243 Earth days to complete one rotation. This makes it the slowest rotating planet in our solar system.

* Retrograde Rotation: Venus rotates in the opposite direction to most other planets in the solar system, meaning the sun rises in the west and sets in the east.

Other contenders for "most extreme" might include:

* Jupiter: Has the largest gravitational pull and the most intense storms in the solar system, like the Great Red Spot.

* Saturn: Home to incredible rings and incredibly fast winds, reaching speeds of over 1,000 km/h.

* Uranus: Rotates on its side and experiences extreme seasons due to its tilted axis.

* Neptune: Has the strongest winds in the solar system, with speeds of over 2,100 km/h.

Ultimately, the "most extreme" planet depends on what criteria you're using to define "extreme."