why did Jesus go to hell for three days  (Catholics only)?

he is still there

Not a Catholic, but I'm answering.  He went to lead the righteous out of Hades, where they had been waiting in a secure place for his coming.  It's called the Harrowing of hell.

Hell is death.  Jesus was dead.  It is as simple as that.

- Theologian

Hell is the grave in NT Geek....hades.

Jesus was IN THE GRAVE three days and nights. 

Jesus didn't go to torments. And catholic is lies.  Catholic beliefs lead to hell.  Catholic and orthodox are not Christian, and they never were.  The first Christians are in Acts in the Bible, and they were obviously not catholic or orthodox.  Catholic and orthodox didn't exist for hundreds of years after the Bible was complete and compiled in the 90s AD. And the King James Bible is 100% perfect and should be the only Bible you read.  But catholic and orthodox lead to torments in hell because they add works to salvation (and "purgatory" doesn't exist).  So get completely away from catholic and orthodox.  Here is what you need to believe:  The Lord Jesus Christ is God, and He loves you.  Believing in the Lord Jesus Christ means being forgiven all sins past and future, and means going to heaven and not hell.  Death leads to immediate heaven or hell, and it is too late to be saved, after death.  All believers still sin.  See 1 John 1:8.  To be in heaven and not hell, believe in the Lord Jesus Christ, who is God and who died on the cross and shed His blood to pay for all of our sins in full, and who was buried, and who resurrected from the dead.  The only way to avoid hell is by believing in the Lord Jesus Christ, without adding any of your own works.  See Romans 4:5, 1 Corinthians 15:3-4, and John 3:16.

Mary Magdalene was booked heavy.

I rather doubt whether there are any Catholics remaining.

-𝒞ℴ𝓇𝓋𝓊𝓈 ℬ𝓁𝒶𝒸𝓀𝓉𝒽ℴ𝓇𝓃ℯ

Because they bought into a corrupt translation. The original was, "He descended into Sheol" where all dead Jews went.