The variety of columnar jointing 'habits' and alarmingly elaborate entablature in the intracanyon basalt flows of western Grand Canyon is eye-popping, to say the least. Some insights into the effects of extremely rapid cooling by river water are available in this collection.

Number two is my favorite with the super-fat columns below the thick and elaborate entablature that is overtopped by an extremely high-calibre (lava-dam failure?) fluvial deposit. A great story there. The bright orange river water in that image is from the big Havasu Creek flood in August 2008.