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Landmarks around the world glow blue for World Autism Day

Altaf Qadri / AP

Humayun's Tomb is lit up in blue to mark World Autism Day in New Delhi, India, April 2.

Franco Silvi / EPA

The Tower of Pisa in Pisa, Italy

Tomasz Gzell / EPA

The Palace of Culture and Science in Warsaw, Poland.

Salvatore Di Nolfi / EPA

Jet d'Eau in Geneva, Switzerland

Maurizio Degl'innocenti / EPA

The lodge 'dei Lanzi' in Florence, Italy