.

During the opening ceremony the Olympic rings turned a lush green. This was to symbolise the fact that 11,000 parading athletes were each given a tree seedling.

Organisers have pledged that every tree will be planted to create an Athletes' Forest in Deodoro, site of the second-largest Rio 2016 venue cluster.

That's not the only envioronmental message in the Rio opening ceremony. Creative director Fernando Meirelles described the state of the planet as, "Past the risky point". The ceremony  urged the expected three billion-plus television audience to sit up and take action.

Giant, NASA-inspired heat maps showed projected effect of sea-level rises on cities including Amsterdam and Shanghai.

The Amazon featured heavily, with one section highlighting the birth of the world's biggest rainforest inducing clouds of luminous yellow butterflies engulfed the stadium and insects marching through the forest.

Could these images inspire students in the SL Evolution topic, or could the games enthuse some in the Human's topic.  On the Olympic website there are Rio Olympics lesson resources;

Sustainable Olympic games

Fernando Meirelles, one of the creative directors of the opening ceremony, explains the green credentials behind that amazing Olympic cauldron we've just seen..., 

A contrast to Rio 2016 could be the 2008 Bejing olympics

In 2008 more than 33,000 exterminators were dispatched to battle a locust infestation in northern China.

"The insects have damaged 3.2 million acres of grassland in three areas near Beijing", the official Xinhua News Agency reported.

"To ensure a smooth Olympic Games and stable agricultural production, we have launched a full prevention plan to prevent and control further locust migration," Bao Xiang, the director of the badly hit Xilingol League grassland work station, was quoted as saying by Xinhua.

Under the plan, some 200 tons of pesticides, 100,000 sprayers and four airplanes were being used to kill the pests, Xinhua reported. The Ministry of Agriculture created a locust prevention and control plan for northern China in late May to prevent an infestation during the Olympics, Bao was cited as saying.

The locusts hatched in early June this year instead of July due to warmer and drier weather conditions, according to the government Web site of Hohhot, the regional capital.