This sparkling display of some four score watercolours from the first decade of the last century throw an unfamiliar light on the artistry of John Singer Sargent (1856-1925), the last great swagger portrait painter in the western tradition. None here is a portrait in the conventional sense: rather Sargent is, so to speak, off duty, painting for himself with a glorious spontaneity, a professional on holiday.

Riveting and bewildering, the 57th Venice Biennale has just opened its myriad doors to the public with several thousand exhibits spread across Venice and its islands.

"In such a night as this..." begins Lorenzo's beautiful speech in Act V of The Merchant of Venice. Watching Shakespeare's play in the Campo del Ghetto Nuovo on a balmy evening under a darkening navy blue sky, with cicadas providing a busy background recitative, it might have been tempting to be lulled by the romance of the surroundings. Belmont itself could scarcely be more delightful than Venice on a moonlit summer night. But Lorenzo and his new bride Jessica talk not of their devotion to one another, but of unfaithful lovers and lack of trust.

Arts festivals the size of the Venice Biennale are inevitably patchy. The appointed directors are hardly ever given enough time to curate and fill absolutely vast volumes of space. They can exhort the many national and individual participants to follow their lead, and yet they have no editorial control over them. And so for this year’s architecture biennale, with its theme of social responsibility – Reporting from the Front – set by director Alejandro Aravena, consider the newly-built Australian pavilion. This proudly features a swimming pool.

Terracotta warriors, Bactrian two-humped camels, Heavenly Horses, Buddhist caves, sand dunes, the world’s first printed book, a silk factory and temples galore including one that was the great mosque in Xi’an, were but some of the ingredients in a breathless first hour in a trilogy of programmes about the world’s oldest trading routes. They were opened up by the explorer and trader Zhang Qian of the Western Han dynasty, about 2,300 years ago.

It can be given to few commercial galleries to have sustained a relationship with the same artist for over 130 years, but such is the link between The Fine Art Society and James McNeill Whistler (1834-1903).

The New Yorker Peggy Guggenheim (1898-1979) was the classic poor little rich girl: insecure, a woman with scores, perhaps hundreds of lovers, longing for love, the writer of tell-all memoirs. What sets her apart is that she was also the creator of one of the world’s greatest collections of modern and contemporary western art. 

Scintillating gems scattered rather thinly through long-winded operas: that superficial impression of Ermanno Wolf-Ferrari’s often delectable music isn’t going to be changed greatly by seeing his first success of 1903, Le donne curiose (“Nosy Women”, perhaps, or, if you want a better English title “The Merry Men of Venice”). It takes an enormous amount of charm to make you want to stay with this inconsequential adaptation of Goldoni – no proto-Feydeau when it comes to comic plotting – and fortunately this Guildhall team have it in spades.

The epic and the intimate combine impressively in Jordanian director Naji Abu Nowar’s debut feature Theeb. The epic is there is the scale of the stunning desert landscapes that are the backdrop – though the desert itself almost feels like a character here, and generic allusions to the Western abound – to his World War One story of complicated Bedouin loyalties played out on the edges of the Ottoman Empire.

Lagoon, miasma and scirocco may seem as far away as you can get from the rolling hills and pleasant airs of the Wormsley Estate in deepest home counties territory. Nor are the bleached bones of Britten’s bleak if ultimately transformative operatic swansong the usual culinary fare many punters might have expected to go with their fine wines and gourmet picnics.