In the process of crafting millions of porcelain sunflower seeds, Chinese artist Ai WeiWei creates a work of art as well as a positive social project for the village in rural China he employed to make the seeds. Follow Sunflower Seeds on its remarkable journey from conception to delivery, and hear the artist talk about his unique socio-political approach to making art. Created by Tate.

English sculptor Barbara Hepworth (1903-1975) was one of the most outstanding female artists of the 20th century. Her smooth, massive sculptures invite their audiences to engage with and even touch them, and they stand as icons of the modern movement. But although a figure of international standing, Hepworth never achieved the same degree of recognition in her lifetime as male contemporaries Henry Moore or Ben Nicholson (her husband of nearly 20 years). Travel to the coastal English town of St Ives, where Hepworth lived and worked until her death in 1975, where many of her sculptures were created and where they continue to stand in the environment they were intended for. If you could see one, how would you interact with a Hepworth sculpture? Created by Tate.

Despite having photographed everything from the Vietnam War to the construction of the Berlin Wall, Don McCullin doesn’t like to be referred to as a war photographer. McCullin has been covering events of global importance since the 1960s by placing himself in the heart of the action armed with nothing but a camera. In this video, he speaks about a series of his photographs in which there are no explicit images of war or violence, but traces of more subtle and insidious instances of conflict, such as the ravaging effect of industrialisation on the English countryside or poverty in major cities. His photographs also illuminate an idea that is central not only to photography, but to art in general: the relationship between text and image. If you had seen any of McCullin's photographs without titles, would you know where they took place, who they depicted, or what message they were intended to convey? For McCullin, the camera can reveal the untold truths of a society. It also serves as a tool for healing, allowing the photographer to not only capture an image through its lens but to engage with its subjects in a unique way. Would you agree? Do you think a camera can change the way you see things? Created by Tate.

Brazilian artist Cildo Meireles joins us at Tate Modern for the artist's first UK retrospective. His work is characterised by a high degree of interactivity, as well as recurring motifs of barriers, fencing and mesh. For a special event at the gallery, Meireles invited members of the public to help create the latest version of his work Meshes of Freedom. Listen as he shares his thoughts on the significance of the work, and why art is not just for the eyes. Created by Tate.

"Every work of art is political because every work of art is breaking new ground," says Colombian artist Doris Salcedo. In this video, Salcedo explains why she decided to literally break new ground in Tate Modern’s Turbine Hall by splitting the floor open with a long snaking crack in her piece Shibboleth. The word “shibboleth” refers to a word or custom that can be used to differentiate one group from another, and is therefore a token of power: the power to judge and reject with violence. What might it mean to refer to such violence in an art museum? For Salcedo, the crack represents a history of racism, running parallel to the history of modernity. As Salcedo comes from a country riven by war, she has always seen conflict and the world from the perspective of the oppressed. The piece is not an attack, but rather a reminder, a question mark and a disruption of the status quo: she invites us to look down into it, and to confront discomforting truths about our world. Created by Tate

Whether capturing images of Frida Kahlo's house, wild dogs in India, or the Seri people in Mexico's Sonoran desert, Mexican photographer Graciela Iturbide presents the world in black in white, or as she describes it, as "an abstraction of the mind." Travelling with her camera every day and often living with her subjects for months, Iturbide says that her process is similar to that of a travel photographer, except that she only shoots "what surprises and provokes an emotion that I want to capture.". Created by Tate.

Since the early 1960s, German-American artist Hans Haacke has been producing controversial work, often seeking to expose systems of power and influence. While some artists might work to engage with local concerns, Haacke brings his art and its topics to a global scale. In this video, he explains his 1978 photographic series A Breed Apart, a group of montages which targets former car manufacturer British Leyland and for its insidious campaigns and actions in apartheid—or racially segregated—South Africa. By juxtaposing slick advertising shots with images of Leyland vehicles “in action,” as he puts it, against the black indigenous population of South Africa, Haacke highlighted the incongruities of the company’s stance. Created by Tate

A major figure in Arab and African modernism, artist Ibrahim El-Salahi discusses his work Reborn Sounds of Childhood Dreams I (1962-3), a large-scale oil painting at Tate. In 2013, Tate Modern presented the UK's first major exhibition of El-Salahi's work, bringing together 100 pieces from across more than five decades of his international career. Take a look at some highlights from one of the most significant figures in African art and learn more about how he belongs to a broader, global art history as well. Created by Tate.

Juan Downey (1940-1993) was a Chilean artist whose innovations in video, sculpture and interactive performance encouraged reflection on perception and the self. Drawing together advances in technology with an interest in the rituals of his native Latin America, Downey asks big questions about society, history, information and the environment. In this video, his groundbreaking 1973 performance Plato Now is restaged and invites the audience members to consider their role in the piece. Created by Tate.

What happens when a priceless work of art is vandalised? Filmed over 18 months, this video tells the story behind the restoration of Mark Rothko’s 1958 painting Black on Maroon after it was unexpectedly graffitied in October 2012. Since being damaged, the painting has undergone over a year of intensive restoration work by the Conservation team and colleagues across the gallery. Nine months of research on how to remove ink from the delicate and aged layers of paint, using special solvents and cleaning methods, were followed by nine months of painstaking work on the painting itself. Would the painting ever look the same again? Is it possible to restore a painting without leaving a trace? Find out on this journey through art, science, and conservation.

Participatory art was a new concept when the exhibition Bodyspacemotionthings first went on show at the Tate in 1971. Created by the American artist Robert Morris, it consists of a series of beams, weights, platforms, rollers, tunnels and ramps that people can clamber all over. It closed just four days after opening, due to safety concerns over the wildly enthusiastic reaction of the audience. Take a look at this 2009 recreation of the piece and listen as curators Catherine Wood and Kathy Noble talk about Morris's vision of art and participation. Created by Tate.

This video brought to you by Tate.org.uk -- Curator Chris Stephens explores the years 1914 & 1915.

This video brought to you by Tate.org.uk -- Curator Chris Stephens explores the 1930s.

This video brought to you by Tate.org.uk -- Curator Chris Stephens explores the 1940s.

This video brought to you by Tate.org.uk -- Curator Chris Stephens explores the 1950s.

This video brought to you by Tate.org.uk -- Curator Chris Stephens explores the 1960s.

This video brought to you by Tate.org.uk -- Curator Chris Stephens takes a look an iconic character in British art, the artist's relationship to Tate, and the work he crafted for a post-war society.

Lebanese artist Saloua Raouda Choucair is famous in the Middle East for bringing abstraction to the region. A rare female voice in the Beirut art scene from the 1940s onwards, she has spent her career combining Western abstraction with the traditions of Islamic design. But working through civil war and ongoing unrest in Lebanon, she remains virtually unknown outside her own country. At the age of 97, this pioneer of art was belatedly recognised with her first major museum show. Here we travel to Beirut to meet the artist's daughter at the apartment where Choucair's work started its journey. Created by Tate.

Snail juice, meteor dust and potatoes... just some of the unusual materials explored by German artist Sigmar Polke. Polke was one of the most significant German artists to emerge in the 1960s, making art in parallel to more "mainstream" Pop in a huge range of materials from painting, drawing and film to potatoes, bubble wrap, and arsenic-based paints. As a young man and self-professed member of a group called the Capitalist Realists, Polke created work that responded to the beginnings of consumer society and popular imagery in West Germany, painting objects like socks, shirts, and plastic tubs in vibrant colours. In the early '60s, Polke worked with halftone images – a printing technique using series of dots, not unlike Lichtenstein's Ben-Day dots – taken from newspapers and other popular printed matter. He later shifted to overlaying images, working with larger canvases, and making use of more unconventional materials. Through his work, Polke confronted difficult truths about the world he lived in – such as Nazism and the Berlin Wall – including those of a consumer, image-driven society. What do you think makes Pop art in Germany so different from more mainstream understandings of Pop, like in the US and UK? Or are the two more similar than they are different? Created by Tate.

Photographer Sunil Gupta talks about how his work in the dark room helped him deal with his HIV positive diagnosis. Sunil Gupta was born in New Delhi in 1953 and went to New York City in the 70s to study business. While there he began to photograph the city’s gay community and continued to use the same subject matter for his subsequent photography series in both India and the UK. A pioneering documenter of LGTBQ stories and relationship – some images from his Ten Years On series are currently on show in Tate Britain’s Sixty Years display. Created by Tate.