When Har Krishan stayed in Delhi there was a Smallpox epidemic and many people were dying. According to Sikh history at Har Krishan's blessing, the lake at Bangla Sahib provided cure for thousands.
Gurdwara Bangla Sahib was constructed in the Guru's memory. This is where he stayed during his visit to Delhi.
Also Gurdwara Bala Sahib was built, where Har Krishan was cremated at the age of about 7 years and 8 months.
