how were aerial photos possible as early as 1860’s in areas where they had no hills or mountains overlooking the city?

Question

how were aerial photos possible as early as 1860’s in areas where they had no hills or mountains overlooking the city?

In: Technology

Answer 1

Hot air balloons were used in 1870 in the Prussian French war. The Prussians besieged Paris and the only way Parisians had to watch their enemy was from a hot air balloon. They used it for surveillance as well as taking arial photographs.