A photo of U.S. President Barack Obama standing in the doorway of a former slave-trading house in Senegal has caught the imagination of people on social media.
The Door of No Return on Senegal's Goree Island is said to be the final departure point of thousands of abducted Africans as they were forced on to slave ships and sent to the United States and other countries in the 17th, 18th and 19th centuries.
"Powerful!" was the most common reaction on Twitter to the photo, as well as to other shots from Obama's visit. Obama is casually dressed in khakis and a white shirt as he peers out at the ocean from the doorway in the side of the aging building, located on the water's edge.
"Seeing this pic of Obama standing at the door of no return in Senegal really makes you think," said one tweeter.
Media, too, picked up on the symbolism of the United States' first black president visiting a building that was at the heart of the slave trade. And Obama himself was quick to point it out.
"This is a testament to when we're not vigilant in defence of human rights what can happen," he told reporters who were with him on his tour of the site. "Obviously, for an African American, an African American president, to be able to visit this site, gives me even greater motivation in terms of human rights around the world."
The Door of No Return is located in the Maison des Esclaves on Goree Island, which lies on the Atlantic three kilometres off the coast of Senegal. Historians have disputed its overall place in the Atlantic slave trade, with estimates the number of people who passed through it ranging from 26,000 to well into the hundreds of thousands. No one, however, disputes that it is a powerful reminder of a brutal era.
Now a museum, the Maison des Esclaves draws thousands of tourists every year. Goree Island itself is a UNESCO world heritage site.