Single-series column charts are represented by rectangular vertical filled areas starting from the horizontal baseline. They are all using the same color, unless you opt for negative values with two alternate colors.
Our US Sales demo charts show totals of product quantities sold in US in three different years. The single series is the US country, and the values for each year are 2007, 2008 and 2009. Remark the horizontal X axis is a category axis: year values are distributed at equal intervals on the axis. All year columns have the same color, unless you also use negative values with alternate colors. Our column charts look like histograms, because they show data of the same kind (i.e. product quantities). Unlike histograms, column charts display often different categories for each point.