Here's the source of the "tower:"
That one red point represents a data point as measured by the Mars Global Surveyor's Mars Orbiter Laser Altimeter (MOLA). As the Mars Global
Surveyor made orbits around the planet, MOLA sent out pulses of laser light and measured the time it took for them to bounce back. From this, they
can determine the height of the terrain. After many orbits, what you get is a map of the height, as measured at a series of points. For instance,
here's an image that shows the measured points in an area covering about 1° of latitude and 0.5° of longitude (about 65 square kilometers)
surrounding the "tower:"
Here's the scale that shows what color goes with what altitude:
MOLA can't tell what the terrain height is between points, but in general, it's assumed the terrain follows a smooth gradient between points. This
how Google builds their 3D terrain, assuming that the ground slopes in a straight line between these measured points.
Let's go back to our one red point:
In that image, each square represents about 0.001° of latitude and 0.0005° of longitude, or a somethinng that's about 60 meters on a side. So we
have a red datapoint in the middle that, according to our color scale, represents an altitude of about 3200 meters. And then we have blue datapoints,
just about 150 meters to the northeast and 120 meters to the southwest, that represent an altitude of -6400 meters. This gives a relative altitude
difference of 9600 meters, or 9.6 kilometers.
So for this to really be a "tower," we have something that is less than 270 meters square, standing 9.6 km tall. I think it's far more reasonable
to assume that this one single datapoint represents a faulty return. It would be improper to conclude that such an anomalous structure exists on the
surface of Mars based on, literally, a single point of altitude data.
You can browse all of MOLA's data on the MOLA Query Page
Planetary Data System.