‘Underland’ review: Darren Aronofsky produces lyrical exploration of the world beneath our feet

Dir: Robert Petit. UK/US. 2026. 79mins

Adapted from the book by UK nature and travel writer Robert Macfarlane, this feature documentary immerses viewers in the dark, silent, almost alien subterranean worlds beneath our feet. Journeying from a cave system in Mexico’s Yucatan peninsula to the storm drains of Las Vegas and the SNOLAB Underground Research Facility in Canada, UK director Robert Petit retains the lyrical wonder of Macfarlane’s writing to make these hidden spaces welcoming and accessible.

Draws the viewer completely into the compelling, unnerving, alluring void

Opening in the UK on March 27 via Dogwoof, the documentary will most appeal to fans of Macfarlane’s work (he has written numerous books, including Landmarks, The Old Ways and The Wild Places). Beyond that built-in audience, the presence of US filmmaker Darren Aronofsky as a producer and Sandra Hüller as narrator may help draw attention, and it should also do well on a streamer or broadcaster. It is an impressive calling card for Petit, who takes a step up from short filmmaking and proves himself an inquisitive and sensitive documenter of the natural world and those who inhabit it.

While Macfarlane’s book sees him visit numerous underground sites, including those in London, Yorkshire and Paris, Petit has chosen to focus on three very different deep spaces and the people who are drawn to them. He starts his journey in Mexico’s Yucatan peninsula, where Fatima Tec Pool descends into an astonishingly beautiful freshwater sinkhole to spend several days journeying into a sprawling cave system, searching for artefacts from her Mayan ancestors.

A world away, underneath the bright lights of Las Vegas, urban explorer Bradley Garrett prowls the city’s labyrinthine storm drains, photographing the detritus he finds there – some offering sobering evidence of human habitation. “Wealth rises,” observes Garrett wryly, “poverty sinks.” In Canada, passionate particle physicist Mariangela Lisanti spends hours in the pristine SNOLAB, two miles down and far away from surface radiation, running experiments in the hope of finding elusive dark matter particles, which may hold clues to life on earth.

All three prove fascinating strands, stories of past, present and future looping and intersecting like tree roots to trace humanity’s longstanding relationship with these deep, secret spaces. In his novel, Macfarlane makes the point that “in the underland, we have long placed that which we fear and wish to lose, and that which we love and wish to save.” That’s certainly evident here, from footage of dumped cars and appliances in underground chasms to Fatima’s emotional discovery of ancient ancestral handprints in the sacred place her people called ‘Xibalba’, the underworld.

Another of Macfarlane’s fascinations is the concept of ‘deep time’; the idea that time underground – in natural spaces at least – is measured not in months and years, but in epochs. That existential idea is given florid voice in Hüller’s poetic, pondering and sometimes portentous (and strangely American) narration (Macfarlane collaborated with Petit on the screenplay), and is also emphasised by Hannah Peel’s dreamlike score and unhurried observational camerawork from Ruben Woodin Dechamps.

With the entire film taking place underground – the camera dives beneath some tree roots at the start and only emerges, blinking into the sun, as the credits roll – there is some clever use of atmospheric lighting, vertiginous angles and graceful, responsive editing to keep things intriguing. With a complete absence of any traditional talking heads – or indeed sunlight – Underland serves to draw the viewer completely into the compelling, unnerving, alluring void.