A highlight is expected to be the symbolic release of nearly 7,000 illuminated white balloons, pegged along a 15-kmstretch of the Wall's former 155-km path, around 1820 GMT. The glowing orbs will begin floating into the night sky from the iconic Brandenburg Gate, the symbol of German unity,to the stirring strains of Beethoven's "Ode to Joy", the anthem of the European Union.