Six million pounds is to be spent upgrading facilities at Wells Cathedral including opening corners to the public for the first time.
The two-year plan includes knocking through a wall to create a doorway so that visitors will enter the cathedral the same way as pilgrims 600 years ago.
A new education centre is also part of the plans and a restaurant will be moved to an upper-floor.
The project was officially launched by former Bath MP Lord Patten.
"We're being able to open up spaces in the cathedral that the public hasn't seen for centuries," said the Very Rev John Clarke, Dean of Wells cathedral.
"It's al all-round vision of what the cathedral can provide in the 21st century," he said.
Two million pounds still needs to be raised for the work to be carried out.
"I very much hope the success that's already been achieved will help Wells get over the finishing line and raise the money still required," said Chris Patten.