An iconic Church which the city was named after, so when you go on the holidays in Sofia, visiting it might be something you should try. This respected site was made under the Serdica’s necropolis, and you can still see the old remains upon which it was constructed as tombs underneath the place. For a time under Ottoman rule, this red brick church was turned into a Mosque, then when Bulgaria got its independence, it was reverted back to a Church and became a great tourism center for the city.