Natural springs defeated the plan, until, years later, the stagnant water was converted to the world's biggest swimming pool.

Stagnant water and a lack of good sanitation could create breeding grounds for cholera and malaria.

Floods and mild temperatures have left many areas covered with stagnant water — the perfect breeding ground for the pests.

And precautions should always be taken for stagnant water.

They transform swaths of rainforest into giant craters filled with stagnant water, where mosquitoes breed and spread malaria.