Christ Church's Tom Tower at sunset, from inside the quad. "Great Tom" (the bell inside) rings every its traditional curfew of 101 tolls each evening beginning at 9:05pm, as it has since the college's 16th century founding (with time off for periodic recastings in the 16th and 17th centuries). Asked how he managed the correct number of strokes each time, the man who used to ring it earlier this century replied "I just count 50, then I count 51."

"Great Tom is cast,
and Christ Church bells ring one, two three, four, five, six,
and Tom comes last"

 

 
The Oxford Botanical Gardens is a great place to relax and see the a garden with more than than a lawn cropped to within microns of the ground (I understand that if you are English, that sort of lawn makes sense)
  The green door separating Christ Church's Deanery from its Cathedral grounds is well known from Charles Dodgson's (Lewis Carroll's) photography

 

 
Statue of Mercury in the centre of Tom quad. Someone has tied an ascott around his neck  
An outer room at the Bodleian library

 

Tower of Christ Church Cathedral, seen from the library (Charles Dodgson's office window). When the Cathedral ws built, trees were planted in the neaby meadow so that, when its main roofbeams eventually needed to be replaced, there would be suitable replacements at the ready; it takes several hundred years to grow roofbeams large enough.
The weathervane atop Oxford's Carfax tower