Complex sentence: Nearing the end of a video you can see the word "MKULTRA", which was a CIA-operated top secret confidential government project concerning mind control human experimentation including using chemicals on test subjects (people) as truth serums.
Split into simpler sentences: Nearing the end of a video you see the word MKULTRA which was a top secret confidential government project. MKULTRA was a project which involved using chemicals on test subjects (people) as truth serums.