Hungary's capital city, Budapest, is truly heaven on earth at nighttime, in summer or winter. Along the river, where you can take an evening cruise, the city's most amazing architecture is illuminated, including Buda Castle, St. Stephen Basilica, the Fisherman's Bastion fortress, Chain Bridge and the absolutely stunning Parliament.
(Special note: Enjoy a New Year's Eve champagne dinner at the Fisherman's Bastion and you can enjoy these views all night long!)
Even though temps hover around 40 during the day and reach below freezing at night, bring your swimsuit for a dip in one of the city's thermal baths.
This city, too, also has a fabulous Christmas market, near the Basilica.