With borders so close and transportation a delight, it's easy to throw a change of scenery and culture into your European itinerary. Here are some of my favorite cross-border day trips.

London to Paris. Zipping on the bullet train from London to Paris (or vice versa), deep below the English Channel (a.k.a. "Chunnel"), is exciting -- and takes just 2.5 hours. Catch an early train, spend about 10 hours in the City of Light, and be back by...

With striking glaciers, craggy peaks and steamy geysers, Iceland appeals to the curious and the adventurous. In recent years, this remote and cold island-nation has vaulted from out-of-the-way backwater to can't-miss destination. Tourism is booming.

Part of the recent travel surge is convenience, of a sort. Nowadays, many Americans are dropping in to Iceland on their way to or from Europe. Both Icelandair and Wow Air typically allow a...

In Germany's southwest corner, the Black Forest ("Schwarzwald") is a range of hills stretching east of the Rhine River. Ancient Romans found the thick forests here inaccessible and mysterious, so they called it "black." Today, Germans and tourists alike are attracted to this most romantic of German regions -- famous for its mineral spas, clean air, hiking trails, cheery villages ... and cuckoo clocks.

Some travelers, driven by "bucket lists," get...