There are several stories about what happened to the ark of the covenant.
I think National Geographic had a program where they explored some old stories about the ark being taken to Ethiopia. I've seen on the monitor where it is supposed to be kept and only special people have ever seen it.
Others think it was probably taken to Babylon and later melted down.
Some think it could be under the temple site where it has been hidden for centuries.
The Indiana Jones movie way back when was about the ark.
Jesus is our ark of the covenant (the place where God dwells among men). He is also our hilasmos (mercy seat, propitiation)
1 John 2:2