Every item must have attribute “type” with any value. I recommend maximum three selected values for this attribute.
Every item must have more than 3 subitems (sub-element)
One of those sub-elements must be URL address to accurate picture of item
Two elements must have any attributes
<place category="city">
<name type ="small" region="malopolska">Bochnia</name>
<population type="small">20tys.</population>
<area type="small">29,9km</area>
<MAMSL type="small">217.18m</MAMSL>
<img url="http://bochnia.pl/wp-content/uploads/2017/03/DJI_0198_arch_resize-2.jpg" ></img>
</place>