Country and city in Codeforces user profiles are often not a the place of the residence but a state of mind. I am sure those 197 users who selected Antarctica as their country feel that their surrounding is cold. Or cool ) The map below shows data from user profiles which have both country and city. So only 16 of all antarctic profiles were taken into consideration, because other have empty city field.
On 27 June 2021 there were 351898 users in the rating list. 88752 profiles contained both country and city. There were 4162 unique values of City field for 180 unique values for Country field. The size of circle is proportional to user number and different colors are used to divide cities on groups with the following numbers of users: <20, 20-99, 100 -249, 250-999, >1000.
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But let's look at some closeups.

The top of the Western hemisphere are:
Bogotá, Colombia 186; Lima, Peru 186; Brasília, Brazil 159; New York, United States 130; Toronto, Canada 124; Havana,Cuba 112; Recife, Brazil 108; São Paulo, Brazil 101.
Some quite valuable cities of other countries are:
La Paz, Bolivia 89; Mexico City, Mexico 85; Santo Domingo, Dominican Republic 67; Buenos Aires, Argentina 60.

There are 13 cities of Eastern hemisphere with number of users more than 1000.

Dhaka, Bangladesh 3645; Moscow, Russia 1985; New Delhi, India 1959; Hyderabad, India 1683; Cairo, Egypt 1530; Beijing, China 1387; Delhi, India 1259; Saint Petersburg, Russia 1245; Tehran, Iran 1190; Kolkata, India 1079; Bengaluru, India 1069; Hangzhou, China 1020; Mumbai, India 1010. By the way Delhi and New Delhi are overlapped, it can be seen more clearly on the closeup below.
Some valuable cities of other country are:
Hanoi, Vietnam 757; Seoul, South Korea 660; Almaty, Kazakhstan 634; Tokyo, Japan 496; Minsk, Belarus 472; Damascus, Syria 467; Kiev, Ukraine 409; Tbilisi, Georgia 330; Amman, Jordan 305; Bucharest, Romania 305.

And some more closeups.

The cities in orange color were not mentioned before.
For India: Pune 929; Varanasi 884; Jaipur 855; Allahabad 848; Chennai 726; Kanpur 668; Ahmedabad 649; Lucknow 614; Indore 524; Patna 518; Ghaziabad 461; Ranchi 434; Roorkee 418; Surat 396.
For Bangladesh: Chittagong 791; Sylhet 697; Rajshahi 393; Khulna 302.

The following valuable cities were not mentioned before:
For China: Shanghai 749; Chengdu 742; Nanjing 732; Guangzhou 580; Changsha 552; Wuhan 465; Chongqing 345; Xi'an 323; Fuzhou 296; Harbin 286;, for Vietnam Chi Minh City 558; for Taiwan Taipei 295.
And finally let's look closer...

...and closer...

So far the following orange cities were not mentioned:
For Russia: Novosibirsk 367 (outside this closeup) and Saratov 304; for Egypt: Alexandria 552 and Giza 268; for Iran Mashhad 256 (outside this closeup).