Songfacts®:

• This was the first Nine Inch Nails single, released on September 27, 1989 ahead of the Pretty Hate Machine album. The song finds frontman Trent Reznor recalling a feeling of being up in the clouds, only to have his euphoria foiled as he comes crashing down: he was up above it, but now he's down in it.
  
  Reznor has said the lyric was inspired by a recent breakup.
• This song found an audience with the industrial crowd, but it was the next single, "Head Like A Hole," that earned Nine Inch Nails a global following. That song got airplay on modern rock radio and won the hearts of techno fans in Europe. In August 1991, the group played the first Lollapalooza, then headed to Europe to tour as the opening act for Guns N' Roses.
• On this track, Reznor drew influence from from the 1986 song "Dig It" by Skinny Puppy. Reznor was an opening act for Skinny Puppy at some shows in 1988.
• The music video has a loose theme of suicide, with Trent Reznor jumping to his death and his decaying body discovered by his bandmates. It was directed by Eric Zimmerman and Benjamin Stokes, who got some aerial shots by attaching a Super 8 camera to weather balloons (this was long before drones), including a shot Reznor's lifeless body, covered in corn starch to make it look like he has been dead for a while. Strings were attached to the balloons to keep the camera from flying away, but they broke, and the rig flew away.
  
  The video was shot in Chicago, but over a year later, the camera, still attached to the weather balloons, was found by a farmer in East Lansing, Michigan, over 200 miles away. The farmer turned it over to police, who looked at the footage and thought it was some kind of satanic ritual murder. The FBI got involved and eventually cracked the case when someone identified the body as Trent Reznor, as seen in the "Down In It" video. The story was reported by Spin and Hard Copy; Reznor was bemused.
• Adrian Sherwood produced this track along with Keith LeBlanc and Trent Reznor. According to Nine Inch Nails guitarist Richard Patrick, Sherwood made his own demo of the song that was more hard-core industrial. Reznor's version, which was the one used, was "really spacious and very simple, almost pop-y."