The man posing atop the wall gives scale to Fort Sanders.
Fort Sanders, Library of Congress
The artillery embrasure left of center would have allowed fire along the face of the wall & into the ditch.
Once someone got into the ditch, by design it was hellishly difficult to get out.
It helps explain the extraordinarily lopsided Confederate loss of 813 casualties vs Federal loss of 20 men inside the fort & another 30 killed by artillery outside the fort.
Confederate attack on Fort Sanders, Library of Congress
These images will help fill in the mental image of what Fort Sanders looked like. The stumps had telegraph wires strung between them. The walls had been soaked with water & were sheets of ice. Attackers who made it into the ditch found themselves in an impossible position. A forlorn hope did make it up the bank, but made made no lodgment.
Engineers Orlando Poe & Orville Babcock, northwest bastion of Fort Sanders. Library of Congress
Confederate attacker's view of the fort. Note man standing in same position of image above.
<ironbrigader.com> Lieutenant Benjamin's Report on the Union Artillery at the Battle of Fort Sanders
Report contains a detailed account of the artillery of both sides.
Longstreet 14,000 men & 35 cannons. Burnside 12,000 men & 51 cannon.