A concrete dome sixty-five metres across looks like a modest thing to put on a World Heritage list, until you stand underneath it. The Centennial Hall in Wrocław was designed by the architect Max Berg and opened in 1913, to mark a hundred years since the Prussian uprising against Napoleon. At the time it was the largest reinforced-concrete building of its kind, and its ribbed dome, rising above a four-lobed hall and lit by a ring of windows, was a daring leap in engineering. Many early modernists took it as a sign of what concrete could do, and it still has the calm confidence of a building that did not need to apologise.
It sits in the middle of an exhibition park laid out at the same time, on the east side of the Oder, with a long pergola surrounding a fountain that shoots jets of water in choreographed shows on summer evenings. Next door is a Japanese garden from the same period, and the grounds hold a zoo, a botanical garden and a tall steel spire made for an exhibition in 1948. On a fine day the park is full of families and people with dogs, and it is one of the pleasantest places in the city to wander without a plan.
The ride that starts from here takes you south-west to two Churches of Peace at Jawor and Świdnica, timber-framed Lutheran churches built in the mid-seventeenth century. After the Thirty Years' War, the Catholic Habsburg rulers allowed the Protestants of Silesia to build only three churches, outside the town walls, with wood, clay and straw and no towers or bells. The result is astonishing: Świdnica's church, with its galleries and painted ceiling, can hold thousands of people and is among the largest timber religious buildings in Europe. The road there, about sixty kilometres, crosses easy farmland on a decent surface and is a pleasure at a calm pace.
Fuel is easy around the park, with stations on the main roads north and south. Park the bike at the hall and walk, as the grounds are large, and tickets for the hall and the pergola are sold on site. Late afternoon light on the concrete is warm, and the fountain show at dusk is worth waiting for.