PRAGUE
https://thatanxioustraveller.com/prague-in-winter-things-do-what-pack/
https://freewalkingtourprague.eu/en/schedule

BUDAPEST
https://theculturetrip.com/europe/hungary/articles/13-ways-to-enjoy-winter-in-budapest/
http://www.triptobudapest.hu/

VIENNA
https://theculturetrip.com/europe/austria/articles/10-reasons-to-visit-vienna-in-winter/
https://www.welcometourvienna.at/the-free-walking-tour/

BERLIN
https://theculturetrip.com/europe/germany/articles/11-cosy-date-ideas-for-berlin-winter/
https://originalberlintours.com/tours/free-original-berlin-walking-tour/

MADRID
https://freewalkingtoursmadrid.com/tour/free-tour-madrid/