TO and TO THE :  When we go to a building (eg .hospital, school, church, prison etc)for the purpose for which it is constructed , we use ‘To’ (without ‘the’).  Otherwise ‘To the’ is usually used.

• He went to school at 8.30 a.m .(  he went to school for studying – See ‘to school’
• The mother went to the school to see her son.( not for studying)- ‘ to the school’
• He had an accident yesterday.  He was taken to hospital immediately.( i.e for treatment) -‘to hospital’
• All his friends went to the hospital to visit him.( i.e not for treatment )- ‘ to the hospital’
• They went to church to take part in the Holy Service. (i.e for worshipping)- ‘to church’
• The mason went to the church for doing some repair works.(i.e not for working)-‘ to the church’
• He went to post office to post a letter.- ‘to post office’
• I went to the post office to meet a friend of mine.- ‘ to the post office ‘
• After conviction, the culprit was taken to prison. – ‘ to prison ‘(i.e a prison is meant for culprits)
• The magistrate went to the prison as a part of his official duties. – ‘ to the prison ‘( not for undergoing imprisonment)