Features of the Olympic opening ceremony

FEATURES OF THE OLYMPIC GAMES OPENING CEREMONY

* The ceremony will be watched by a crowd of 50,000 in the Maracana Stadium and a television audience of 3.5 billion.

* Former soccer great Pele may light the Olympic flame.

* British actor Dame Judy Dench will read a special poem in a recorded segment.

* Samba will be a key element, with 12 dancing schools involved.

* Marching athletes will be presented with a tree seed in soil which will later be planted in a park in Rio to create an Olympic forest.