Members of Library of Birmingham staff, council representatives and Carillion employees gathered in the dramatic rotunda which will house the five-storey book wall.
The rotunda, at the very heart of the library, features a series of cantilevered circular balconies each providing access to a different part of the shelves that comprise the book wall.
Escalators zigzag across the space, providing stunning views throughout the library and access for all to over 400,000 books, more than double the amount currently on show at Central Library.
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Patchy rain around today, but the next few days are expected to pick up.
The route of the ride is a 6km loop around Leicester, and people can join in at any time before it ends at 4pm.