In chemistry, a covalent bond occurs when two atoms share an electron, merging together to produce a stronger, more permanent structure.

The Challenge 40 Reunion Part 2 was released recently and continued the drama. It revealed secrets and hookups that viewers were not ready to see.

A secret hookup, the end of the Vacation Alliance, a surprise appearance from TJ — this reunion special had it all.

The contestants return for a reunion to discuss unresolved issues in the second part of "The Challenge: Battle of the Eras" ...