For exploring the old centre of Leiden in the evening, a guided walk is truly recommendable.
Not that Leiden is a dangerous place ! Not at all, it is very safe.
But simply because finding your way in these little winding streets in the dark is not always easy. See this visitor's review.
In Leiden, you'll find peace and quiet in most places. At least here you can hear your footsteps in the cobblestone streets. Which is becoming ever more difficult in bustling Amsterdam.
In Leiden you can find yourself alone with history. Just imagine bumping into young Rembrandt, coming round the corner. Or when walking along the foot of the castle, towering gloomily in the dark. In December, the lights of Christmas make the streets and canals even more fairy-like and romantic. Leiden is home to the only floating Christmas market in the Holland.