Machu Picchu.

Start in Cusco’s main square to read the cathedral and Jesuit church against the surrounding arcades. It is the clearest orientation point for a historic-center walk.

The square lets you compare two major colonial facades at once while the arcades show how the city’s civic center still works. Begin here before choosing an indoor museum or heading uphill; the surrounding buildings deserve separate visits. The central fountain gives another fixed orientation point.

• Arcaded sides frame the cathedral and Jesuit church.

Walk the full perimeter before entering either church so their different facades are easy to compare.