Oxford is a city (well) explored by foot or bicycle. There is no central campus so it is important to plan your visit advance, perhaps drawing up a list of places to visit and (plan) your route between them. The (follow) resources may be useful.
Most colleges are open throughout the year, at least for potential(apply) to walk around the grounds. Our Visiting colleges page (give) details about opening times any admissions charges which may apply, though many (college) give up these for potential applicants. You can checkcolleges offer the course you are interested in before you visit and perhaps read our advice on choosing college.
