Miroslaw Balka's installation 'How It Is', in the Turbine Hall at the Tate Modern, is only on show until 5th April. Go and see it, preferably on a week day when there are fewer screaming children and touristic types with cameras and glowing mobile phones which ruin the effect of the piece.
The bunker style box which can be entered with a ramp, contains no light source, demanding total trust from the interactive viewer. You have to make a decision as you reach the top of the ramp and approach the threshold of the bunker; whether to proceed into the pitch black, or to turn back. If you do decide to go on, your senses will make you aware of others around you whom you can't see but can hear. As you progress into the darkness, fear may intimidate. Will you go further? How much further is there to go?
The installation provides an astonishingly accurate metaphor for the experience of living. The darkness ahead isolates almost totally except for the dim impression of others journeying with you. When you turn back, you see more clearly where you have come from. Wow.