For 512 hours, the Serpentine Gallery will lend its three exhibition rooms to enigmatic 67-year-old Serbian artist Marina Abramovi?. For the duration the empty space will be occupied by Abramovi?, her assistants, and the public - together they form ‘the performing body’. Abramovi? is already in residency and her epic, improvised performance piece is underway.

7 things ELLE noticed when we visited 512 Hours:

1) You have to leave everything - your bag, jewellery, phone (etc) in a locker outside the exhibition - the only thing you are allowed to take in is yourself. (Note: do keep your clothes on).

2) Abramovi? and her assistants (dressed in head-to-toe black) lead the public around by hand, often at a glacial pace.

3) Abramovi? whispering things (indecipherable during our visit)

4) Fellow strangers staring at themselves in hand-held mirrors whilst attempting to walk backwards.

5) People sitting on chairs with their eyes shut.

6) People lying on the floor with their eyes shut.

7) One person doing downward dog.

You can use the atmosphere Abramovi? creates for reflection or observation; ponder your own thoughts, or people watch. Think of it as a surreal, artful tube ride, only everything is cranked down to super-slow mode and there is no final destination (in the physical sense, at least). It’s powerful, and disconcerting in the best way possible.

Marina Abramovic: 512 Hours until August 25 at the Serpentine Gallery