When I took this photo, it was just after nautical twilight so it was quite dark outside, except for fireflies twinkling all over the fields. This is a 5 second exposure with an 85mm f/1.4 lens and ISO 6400, then I boosted the exposure by about 2-3/4 stops in Lightroom.

The pinkish area near the top is the red beacon light atop the RWD water tower several miles away.

It's interesting how some of the fireflies flash their lights, showing up as a row of dots, while others glow for longer periods, creating a long streak.