Today is the 10th anniversary of one of the worst terrorist attacks on the UK.
On 7 July 2005, four men with rucksacks full of explosives attacked central London.
More than 50 people lost their lives and hundreds more were injured.
The attacks became known as the 7/7 bombings.
When the attacks happened there was lots of help and support from doctors, police and the fire service .
Ayshah spoke to Jason Killens who works for the London Ambulance service, about how the emergency services helped during in the attacks.
In total, 52 people died in the 7/7 bombings, and more than 770 people were injured.
Esther Hyman lost her sister Miriam in the attacks.
She is proud of how people came together to help and support each other after the attacks.
These types of attacks are very rare in the UK, and police, the government and security services are taking measures to try to stop events like 7/7 happening again.