500x333 | 143K | jpg free download |
119x79 | 24K | jpg free download |
300x200 | 63K | jpg free download |
1024x683 | 544K | jpg free download |
1600x1067 | 1M | jpg free download |
Overgrown fortifications (crenellations, US crenelations) on top of an ancient stone city wall in the Italian city of Pisa.
By the mathematics department of the University of Pisa.
500x333 | 143K | jpg free download |
119x79 | 24K | jpg free download |
300x200 | 63K | jpg free download |
1024x683 | 544K | jpg free download |
1600x1067 | 1M | jpg free download |