The city's most staggering discovery is the brutalist National Library building, a structure so bizarre and seemingly out of place that many are left unsure as to what to make of it. It still is a perfectly functional library, so do drop in to get a good look at what's inside – you might just chance upon an English-language exhibition.

This interactive museum is an exceptional place to gain a deeper understanding of Warsaw’s history. It was founded in commemoration of an event that profoundly changed the city: the Warsaw Uprising of 1944. Listen to the oral accounts given by insurgents, go down into the sewers — similar to the ones that insurgents used to move around the city — and see The City of Ruins, a bird’s-eye view of Warsaw burnt to the ground. Don’t forget to see the murals painted by Polish artists on the Wall of Art. The museum building is interesting in its own right since it was previously an old electric power plant for trams.

Ottenby, on the very south of the island of Öland, is one of the top areas for birding in Sweden — 377 species have been observed here. A visit to Öland offers fantastic opportunities for bird studies all the year round. Ottenby Bird Observatory was founded in 1946 and has ever since performed studies on migrating birds. Around 20,000 birds are ringed each year. Also, the bird observatory is involved in bird migration research projects on the island of Capri, Italy, and in Nigeria.

The Romanian Athenaeum concert hall is home to the superb Filarmonica George Enescu and the hub of Bucharest’s musical activity. Exquisite mosaics and historical frescoes adorn the 19th-century circular building, which hosts impressive orchestral concerts and other performances. You can visit the ornate, domed, circular building without attending a concert, too.