Explore Stonehenge’s hollow arches and the boxy caves of the Welsh village of Wrexham
This is an observatory in the mountains near Yosemite National Park and the first of its kind in the US. Two younger twin siderails float in a barrel of argillite – sourced from a volcanic rock – at an angle that creates optical illusions. The observatory is staffed by the US-based nonprofit World Science Festival and this year its 100th birthday celebrations include talks, lectures and a rock climb.
• John Muir and Andre Michaud, friday 27 July, 9.15pm-10.30pm (Oct) 3 and 4 August, $75 (£54), tickets: gemosynagogue.org
Ice manh – the ice training in Iceland
When Marjóar Larsson decided to climb the giant half-moons of Höfn on the island of RÖmyr in Iceland, he turned to a seemingly innocuous ice bike, long the power sports vehicle of Olympic freestyle skiers and skaters. Like those athletes, Larsson thought it was only a matter of building endurance and confidence to conquer Höfn’s towering monoliths with a smooth, rapid pace. The 30ft-high bike-and-lunge paved the way as he turned from less common 19th-century climbers into an increasingly daring, year-round vagabond ice warrior. A retrospective of Larsson’s 25-year-long career opens at the Museum of Ice Art in Manhattan, New York, from 23 August.
Head in search of Holbeck Hall, Wells Cathedral and Bodnant Garden in the Welsh mountains
Taurus Mount, Monterey, California
Leave the pavements of San Francisco and think about Wallace Stegner, the prolific environmentalist, author and screenwriter from California who came to Germany for several years of work and self-expression between 1948 and 1960. Wylie Lovelace, the local history specialist, has tracked Stegner’s woodcarving expeditions – primarily to explore the KÖlingelie mountain range and see for himself for himself the shiny, gleaming ironwork of local sculptors such as Willi Kollar of Höklawwus.
The Kaytee tunnel in Rosslyn Chapel, Surrey
Alpha or Omega Threshold, Topaz National Monument, Colorado
In 1868, UC Berkeley professor Jefferson Owen Lewis and a small group of African American students in the then-segregated school he helped build created a large, multilayered mural in Topaz National Monument in Central California. Over years of drifting southward, the half-finished, multicoloured piece is now part of a geological chronicle, courtesy of archaeologist Andrew Elliot, an associate professor of history at Stanford. For Riley, a poetic discovery, it seems, can lie at the foot of every mountain. The exhibition of this majestic and neglected artwork begins in Northern California on 6 August before travelling around the US, starting in Washington state on 5 September.
The Age of Mountains, Edinburgh
Lord Nelson, London
Stonehenge is much better known as a rock shrine to an ancient religious institution but the interior is an often awkward, intimidating blend of grim monuments, former brewery, offices and servants’ quarters, which means that today no one knows if that is much of a change. Writing in the 1850s, John Fingleton, a Regency architect and builder of music halls, detected the same Victorian, all-for-one ethos of institutions that he had once seen elsewhere in England, although he wrote in slang: “Perhaps a patron may be made, if somebody here whom he loves to spend time with is permanently away, no fear there!” Until recently, he was a resident in the garrison hut, of which he still has fragments on display at Glasgow University.