On a warm summer's day in Wroclaw, Poland, Darek Fidyka walked across a bridge, using only a frame for support. This had been his dream for four years, after he was paralysed in a knife attack. Now, after a transplant of cells taken from his nasal cavity, it had become reality.
He is the world's first patient to receive the groundbreaking treatment. Behind those few steps lay the extraordinary efforts of a group of scientists, surgeons and fundraisers in Britain and Poland.
Dr Tabakow was so convinced of the science that he got ethical approval to inject OECs from the nasal lining into the spinal cords of three paralysed patients - this was crucial to show the procedure was safe. None suffered ill effects.
The next patient was Darek Fidyka. Before surgery, Dr Tabakow insisted Mr Fidyka underwent eight months of gruelling physiotherapy, in order to test whether there was any chance of a spontaneous recovery. He performed delicate surgery to open the skull in order to remove one of Darek's olfactory bulbs, at the base of the brain, and a second operation to expose the damaged spinal cord and transplant the cells. For future patients, Dr Tabakow is pioneering a new technique to remove olfactory bulbs through the nose - a far less invasive procedure.
It must be stressed that the results of one patient are not adequate evidence that this cell transplant therapy works. All the scientists involved are keen not to raise false hopes.
The procedure must be successfully repeated in other patients, in a clinical trial. That is likely to take many years - only then will it be clear whether this marks a new era in the treatment of paralysis.
