Barcelona's best-known street: the 2017 attack and its memorial, the rebuilding works running to 2027, the Liceu opera house, the Boqueria market and what became of Bar Pinotxo.
Gaudi's apartment block on the Passeig de Gracia, known as La Pedrera: a stone front hung on a steel frame, no load-bearing internal walls, and the witch-scarer chimneys on the roof.
Gaudi's hillside park above Gracia, built as a housing estate that failed. The monumental zone is ticketed, timed and capped, and must be booked; the woods above remain free.
Antoni Gaudi's buildings in Barcelona: the Sagrada Familia, Park Guell and Casa Mila have pages of their own, with Casa Batllo, Casa Vicens, Palau Guell and the crypt at Colonia Guell beside them.
Barcelona's cathedral, built between 1298 and 1448 behind a neo-Gothic front of the 1880s paid for by a banker, with the cloister, the thirteen geese and a roof reached by lift.
Four Montreal museums worth a visitor's time: the Museum of Fine Arts, Pointe-à-Callière over the city's founding site, the Canadian Centre for Architecture and the Montréal Science Centre.
Saint Joseph's Oratory is the largest church in Canada, built at the urging of the lay brother canonised in 2010 as Saint André Bessette. The cross on its dome is the highest point in Montreal.
Peter the Great founded this monastery in 1710 on the spot where Alexander Nevsky beat the Swedes on the Neva in 1240. It was the wrong spot, and the city's own encyclopaedia says so.
The river town fifty kilometres east of Helsinki: the arson that destroyed the cathedral roof in 2006, the Diet of Porvoo, Runeberg, and why there is no train.
Mannerheim, Alvar Aalto and Artists' Hill; Finland's largest war cemetery and the wars it actually fought; why Sibelius is not here; and how the cemetery is really laid out.
The Suomalainen brothers' church cut into granite in 1969: why the air-raid-shelter story is wrong, what the interior does, and the admission charge it introduced in 2017.