Botanic Gardens
Another of our trips over Christmas break was to the US Botanic Gardens. They are said to have a great train display which encompasses an entire wing of the building. But it was 20 degrees and windy and the line was around the corner, so we decided to skip it and headed straight into the rest of the building.
There were great plant covered models of the major buildings and monuments in DC:

The highlight for Luke was riding the metro:
