The National Police Memorial is a memorial in central London, commemorating about 4000 police officers killed in the course of their duties in the United Kingdom.
Since the uprising began 19 months ago, he has printed posters commemorating about 300 people.
BBC political correspondent Iain Watson says that while Mr Cameron wanted to use his speech to talk to young people about commemorating the past, the year 2014 also has a contemporary significance.
About 5,000 visitors arrived to commemorate the occasion, the largest crowd for any open house.
I've been thinking about this journey, commemorated now by the counting of the omer, the seven weeks between Passover and Shavuot, and I've been reflecting on that moment when our anxious ancestors waited at Sinai to receive the Torah.
To commemorate the occasion, the YouTube team has shared some stats about the initiative.
In 2008, the village commemorated the first race's centennial in a parade featuring about 60 antique cars.
"Today is really about commemorating the Sikh contribution to the armed forces both today and in the past," said Lt Col John Kendall, who organised the event at the Indian War Memorial room at Sandhurst.
"The 28th [June] isn't about commemorating the coup, it's about repudiating it.
About World AIDS Day World AIDS Day is commemorated around the globe on 1 December.
