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# Lie back in a church and follow London’s buried rivers
- URL: https://www.killscreen.com/lie-back-in-a-church-and-follow-londons-buried-rivers/
- Published: 2026-10-12T17:50:49.000Z
- Updated: 2026-10-12T17:50:49.000Z
- Description: Marshmallow Laser Feast’s Water Body is the Special Presentation of LFF Expanded, the BFI strand that programs games beside film.
- Author: Kill Screen Staff
- Tags: News, Marshmallow Laser Feast, Immersive, Installation, London, LFF Expanded, ecology, #radar-item, #events

Event details

When

Oct. 3 to Oct. 18, 2026

Where

The Hall, St Martin-in-the-Fields, London

Cost

£6 to £12

[Get tickets](https://whatson.bfi.org.uk/lff/Online/article/water-body-booking-lff26?ref=killscreen.com)

The experience starts with a cup. At The Hall in St Martin-in-the-Fields, through Oct. 18, *Water Body* opens by handing you a ceramic cup of water, made by ceramicist Ludmilla Balkis, before you lie back and let Robert Macfarlane's voice and James Bulley's composition route you along London's buried rivers and out into planetary water systems. Thirty minutes, parts of it in complete darkness, [tickets from £6](https://whatson.bfi.org.uk/lff/Online/article/water-body-lff26?ref=killscreen.com).

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The **Water Body* trailer, via [the studio’s announcement](https://www.instagram.com/marshmallowlaserfeast/reel/DdmK4SyMnXU/?ref=killscreen.com).

The studio is Marshmallow Laser Feast, and the picture around you is not a film. The work renders Earth-systems datasets in real time, compressing a year of planetary water movement into ten seconds, with spatial sound that changes with where you are in the room. Illustrations come from Elena Landinez, and the whole piece leans on *Is a River Alive?*, the Macfarlane book that supplies its epigraph: "Rivers run through people as surely as they run through places."

[The studio's own announcement](https://www.instagram.com/p/DeKCq0fDOD1/?ref=killscreen.com) calls *Water Body* the Special Presentation of LFF Expanded, "the BFI London Film Festival's programme of immersive art, extended reality and video games," curated by Ulrich Schrauth. The same program runs a free games lounge at BFI IMAX this month. 

Marshmallow Laser Feast has worked this lane for a decade, usually with an engine under the hood. Last month we covered [the studio's Singapore show, where whale songs drive the render engine](https://www.killscreen.com/whale-songs-drive-the-render-engine-in-a-singapore-show/). *Water Body* swaps the whale for the water table under Trafalgar Square, and the controller for a cup you hold with both hands.

![](https://storage.ghost.io/c/25/84/2584b75d-4bd6-4cce-8259-f1d1c65abbb5/content/images/2026/10/waterbody-2.jpg)

![](https://storage.ghost.io/c/25/84/2584b75d-4bd6-4cce-8259-f1d1c65abbb5/content/images/2026/10/waterbody-3.jpg)

![](https://storage.ghost.io/c/25/84/2584b75d-4bd6-4cce-8259-f1d1c65abbb5/content/images/2026/10/waterbody-4.jpg)

Ceramic cups by Ludmilla Balkis; stills courtesy Marshmallow Laser Feast.

Killscreen covers what happens when games, film and immersive art end up on the same bill, and the free KS Radar letter is where it lands first. Three short issues a week, no charge.

[Get the free letter ](https://www.killscreen.com/start/?ref=radar-cta)