One of Poland's greatest tourist attractions is the Wieliczka Salt Mine outside of Kraków. A truly amazing visual experience, it also does a roaring trade in health breaks, where the inhalation of salt has been claimed to have been helpful in the treatment of respiratory ailments. Poznań now has its own underground 'salt grotto' thanks to the ingenuity of the owners here, who have brought in kilos of salt from the Dead Sea to create a glistening underground cavern. While Poznań's salt cave may not have underground lakes and chapels carved entirely from salt to wonder at, it does boast all the health benefits of breathing in salty air. In fact, 50mins in the salt grotto gives you the same effects as an entire day spent on the seaside. Located under an Old Town tenement metres from the Rynek, children are welcome (bring your own toys and books, or use the ones on site) and yoga classes are also held inside.