The Dark Tower in the constellation of Scorpius is an elongated dark cloud of dust and gas embedded in a rich sea of stars. It is known as a cometary globule. The intense UV radiation from very hot OB-type stars in NGC6231 (off the top edge of the image) sculpts the resulting columnar structure of the Dark Tower. The UV radiation is sufficiently strong to ionize hydrogen, producing an pink glow around the top of the Dark Tower and similarly to ionize the background medium, such as the interesting "bridge to nowhere" of H-alpha light extending from the tip of the Dark Tower toward the left side of the rotated image.
In the image we can see several blue reflection nebula embedded within the Dark Tower, which are stellar nurseries. The Dark Tower is 40 light years across and 5,000 light years distant.
Credit: Anne's AstronomyI uploaded two versions of the image, one in the original position it was captured and other rotated 90 deg CCW, which corrsponds to the view of the most images posted in the web

This image is a stack as follows:
Ha: 15x 20' bin 1x1
RGB: 12x 15' bin 1x1
Bias, Darks and Flats applied

Scope: Skywatcher Esprit 120mm f/7
Mount: Skywatcher EQ-6 Pro
CCD: ST-8300M
CCD Guia: Lodestar
Processing: Pixinsight

Note about Processing: In this image I have not added Ha data to the Blue's and Green's channels as most of the processing of the images in the web. I added only to the red channel, after subtract from the true red's channel the Ha's content, create an index and then add the Ha to the red, using percentages of this index.