<p>The world's deepest freediving pool has opened in Poland.</p><p></p><p>At 45 metres deep, 'Deepspot' holds 8,000 cubic meters of water, which is nearly as much water as 27 Olympic-sized swimming pools.</p><p></p><p>The venue will serve as a training centre for the army and firefighters.</p><p></p><p>Its facilities include a hotel with underwater views along with a tunnel for spectators and a restaurant.</p>