Oxford University and its colleges will host numerous activities, behind-the-scenes tours, and special openings this weekend.
The events are part of the annual Oxford Open Doors, which will return on Saturday and Sunday, September 14-15.
The event is a celebration of people, heritage, community, culture, science, and research and opens places not always accessible to the public.
More than 100 buildings will open their doors for free, with family activities, exhibitions, and tours planned.
Anna Eavis, Oxford Preservation Trust's CEO, said: "Oxford Preservation Trust is the proud organiser of Oxford Open Doors.
"We’ve been running this extraordinary event since 2008, giving everyone in Oxford the chance to freely explore all aspects of their city.
"Oxford Open Doors enables you to experience - free of charge - the city’s oldest and newest buildings, its gardens, its hidden corners, and its many, many surprises.
"And you’ll discover how these places are used today, for innovation, research, art, culture, and community."
Oxford's colleges, including Harris Manchester, Christ Church, Pembroke, Worcester, Exeter, Mansfield, Wolfson, St John’s, Magdalen, Reuben, Balliol, Green Templeton, Wadham, Kellogg, Somerville, St Cross, St Edmund Hall, and New College, will welcome visitors for events and openings.
Behind-the-scenes tours at the university have proven popular, with many booked up in advance.
These tours offer a unique opportunity to explore the Schwarzman Centre for the Humanities, Oxford University Press, the Sherardian Library of Plant Taxonomy, and the Radcliffe Camera with Bodley's librarian, Richard Ovenden.
Visitors will also have the chance to explore the Radcliffe Humanities building, which was once a hospital named the Radcliffe Infirmary, from 1770 to 2007.
Oxford Open Doors also offers the opportunity to learn about places such as the Real Tennis Court at Oxford University, where visitors can watch the forerunner to lawn tennis played in the 18th-century court.
There will also be family-friendly tours to see behind closed doors at the Weston Library and letterpress printing at the Bodleian Old Library.
The Blavatnik School of Government will be open for self-guided tours and there will be guided geology walks at the Museum of Natural History.
The courtyard at Oxford Castle will see professional stone carvers at work, music from the City of Oxford Silver Band and the Ghaetta Medieval Band, and 1,000 years of history at the castle and prison.
Ms Eavis added: "We owe enormous thanks to all those who open their doors for us and to our many brilliant volunteers, who work so hard throughout the weekend.
"We’re also grateful to the University of Oxford for its support."
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