Temple of Mars Ultor in Rome

You're standing at the remains of the Temple of Mars Ultor, Mars the Avenger. This was the centrepiece of the Forum of Augustus, and the most important temple Augustus built in Rome. Look at the high podium and the columns still standing. The temple sat on a raised platform, lined with eight Corinthian columns along the front and each side. It was all built of white Carrara marble. The back had no columns at all. It leaned against a tall wall that separated the forum from the Subura district behind it. Can you spot that wall behind the temple?