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