Christ Church Spitalfields began renovating it's crypt in 2005 after completing refurbishments to its nave that year - work also celebrated by the Prince of Wales.
It's crypt is a part of various ministries including with children and their parents, young people, the homeless, ex-offenders and it also has a cafe. It's thought thousands use and benefit from the crypt each week.
Prior to its refurbishment work the crypt was full of graves and tombs which have since been exhumed and, because they were so well preserved, have now become the most studied human remains in British history. They reside at the Natural History Museum.
Local schoolchildren greeted the Prince of Wales with their own rendition of the popular Christian hymn, Here I Am to Worship:
Prince Charles then met scores of guests from Christ Church Spitalfield's various ministries:
He then gave a speech thanking everyone for their contributions to make the renovation of the crypt possible, before the Bishop of London Rt Revd Richard Chartres gave a blessing.
Speaking to Premier Revd Andy Rider, the vicar of Christ Church Spitalfields, said: "The Prince of Wales is well-known for his views on architecture - to fit into the framework of reference that he approves of is great.
"This is a Grade 1 Listed building - we wouldn't want to do anything with other than the very best.
"Because he was here eleven years ago and he opened up the restored nave... this in a sense is a completion of the church building.
"My prayer is that when people look back they don't tell stories of the buildings that we're telling today, but they tell the stories of lives transformed, communities established and built up, and a growing church."
Listen to Premier's Aaron James speaking to Revd Andy Rider: