Mount Roraima - a table-top mountain located at the junction of Brazil, Guyana and Venezuela. With an area of about 50 square km the plateau is equivalent in size to the four smallest countries in the world.
Straying a little off topic - a rather evil looking Moreton Bay Fig tree (aka Banyan) in Balboa Park, San Diego. Big Mummy Triffid springs to mind...
A supercell thunderstorm in Texas. One of the four classifications of thunderstorm, supercells are the least common, but most destructive. This one looks like a giant dugong hoovering up everything in its path.
I included that one because there is a similar tree in the Botanic Gardens back home in Rockhampton - older, much bigger and actually friendly looking. It provides welcome shade for the outdoor eating area of the cafe in the gardens as well as for peacocks, galahs and rainbow lorikeets. A favourite haunt of ours, my wife and I both miss it.
The Wave - a sandstone rock formation in Arizona. Popular with hikers, the colourful, undulating forms are so fragile that access is limited to 16 people per day - and permits are issued two days prior to visiting on a lottery basis.
Straying off topic again but I thought this too good to not include - an Italian slant on a tree house in the Lombardy comune of Sirmione.
The Fly Geyser in Nevada, USA. Situated on a private property called the Fly Ranch, it's a geothermal geyser that has constant streams of water spouting five feet into the air, depositing minerals and multi-coloured algae onto the surrounding terraces.
fabulous, you couldn't make that up if you tried. Slightly uncomfortable that it is on private property but it does keep it pristine.
The 'underwater waterfall' in Mauritius - an optical illusion that I really can't get my mind around.
The Bungle Bungle Range in Western Australia's northernmost region - the Kimberley. 175 square miles containing thousands of beehive shaped, orange & black/grey sandstone rocks, 200-300 metres high. The name is thought to be derived from a word in the language of the traditional owners, the Gija people - banggul banggul, a type of cockroach, the striped colourings of which are similar to the rock formations. If provoked, the cockroach has an alarming defence mechanism - it squirts urine at the culprit.
The Arches National Park in Utah - which contains more than 2000 sandstone arches - the highest density of natural arches in the world.
One for @Mexican Hornet ... Taam Ja' - the world's deepest known underwater hole. Situated in Mexico's Chetumal Bay, the bottom of the hole is yet to be reached, but it's estimated to be at least 420 metres deep.
Off topic again, but a wonderful shot of the Pacific Ocean sizzling as lava from the Kilauea volcano flows into it - shrouding Hawaii with steam.