The Oxford has been continuously operating since 1891 — Denver's oldest hotel, designed by Frank Edbrooke (also of the Brown Palace). The lobby is a beautifully preserved Beaux-Arts space full of original art deco fittings added in the 1930s; the Cruise Room Bar, opened in 1933 the day Prohibition ended, was modelled on a lounge of the Queen Mary and is a National Historic Landmark in its own right.
Drinks at the Cruise Room are reason enough to walk over. The hotel's restaurant Urban Farmer is also one of LoDo's better options. Stay or visit — either works.