Upgrading from:

Histograms`

As of Version 7, the Histograms Package has been integrated into the Wolfram System.

Histogram is now a built-in Mathematica function:

Version 6.0 << Histograms`;
Histogram[RandomReal[NormalDistribution[0, 1], {1000}]]

Histogram3D is now a built-in Mathematica function:

Version 6.0 << Histograms`;
Histogram3D[RandomReal[NormalDistribution[0, 1], {100, 2}]]