It has been likened to a monster, an oil rig – and the Parthenon. Now, for its 40th birthday, the astonishing London landmark has joined the Open House festival, to grant admirers a rare look around the inside

In his 2012 book A New Kind of Bleak, the critic Owen Hatherley called it “monstrous, compelling” and utterly messed-up. Back in the 1980s, a then Prince Charles suggested it had been inspired by a North Sea oil rig. But none of this stopped it from becoming, in 2011, the youngest ever building to be given Grade I-listed status in the UK.

And now, as part of its 40th anniversary celebrations, the Lloyd’s building will open to the public for the first time since 2014 for one day only during London’s Open House festival. The iconic building in the heart of the financial district was designed by architect Richard Rogers to house the global insurance marketplace. Its futuristic facade has been a celebrated part of the City of London skyline since it opened in 1986, but the interior is rarely seen by the public. Visitor galleries with a view of the trading floor have long been shut for security reasons.

Creating homes for Frank Sinatra, Cary Grant and Lucille Ball made Williams a star. A trio of new exhibitions shows he belongs among the 20th century’s greats

When you fly into the Los Angeles airport LAX, a spindly space-age contraption is the first thing that greets your eyes outside the window. Built in the early 1960s, the Theme Building – which once attracted travelers to its in-house restaurant, designed by Walt Disney Imagineering, towering above airfields – was built by a supergroup of architects whose structures helped define the city’s midcentury aesthetic: William Pereira, Welton Becket, Charles Luckman and Paul Revere Williams.

Of these architects, Williams, the first licensed Black architect in California, arguably shaped the contours of Los Angeles most deeply. In the six decades before his death in 1980, Williams completed an estimated 3,000 structures ranging from single-family residences, commercial buildings, affordable housing projects, the Los Angeles county courthouse, a reimagining of the now-razed Ambassador hotel and opulent homes for celebrities including Frank Sinatra, Barbara Stanwyck and Lucille Ball and Desi Arnaz. Perhaps most iconic of all is the Beverly Hills hotel; Williams led its renovation, and its recognizable curlicued sign is scrawled in Williams’s own handwriting.