Goree Island, Senegal

The "House of Slaves" on Senegal's Goree Island was, by some accounts, a first stop for some 20 million African slaves destined for ships moored in the deep waters off Goree's rocky shores.

CBS visited the island in advance of President Obama's visit this week. Despite some debate about Goree's role in slave history, Obama and two other U.S. Presidents, George W. Bush and Bill Clinton, have made the same pilgrimage, as has Nelson Mandela.

Goree and the "Slave House" exist as powerful symbols of the slave trade and that alone makes it a place of curiosity and history.

In this photo, the castle on Goree Island can be seen with defensive cannons visible, June 26, 2013.

Goree Island, Senegal

The Statue of Liberation, Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The Statue of Liberation, Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

Entrance to the House of Slaves (Maison des Esclaves), built by the Dutch in 1776, Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The men's jail quarters inside the House of Slaves (Maison des Esclaves), Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The "Door of No Return" inside the House of Slaves (Maison des Esclaves), Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

A tourist in the threshold of the "Door of No Return," the House of Slaves (Maison des Esclaves), Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The women's jail quarters inside the House of Slaves (Maison des Esclaves), Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The cell for "recalcitrants" inside the House of Slaves (Maison des Esclaves), Goree Island, Senegal, June 26, 2013.

Goree Island, Senegal

The Slave House courtyard, Goree Island, Senegal, June 26, 2013.

U.S. President Barack Obama looks out to sea through the "Door of No Return," at the slave house on Goree Island, June 27, 2013.

Obama called his visit to a Senegalese island from which Africans were said to have been shipped across the Atlantic Ocean into slavery, a "very powerful moment."

President Barack Obama and his wife Michelle look out from the Door of No Return while touring the House of Slaves, or Maison des Esclaves, at Goree Island off the coast of Dakar on June 27, 2013.

First Lady Michelle Obama (C) walks with her mother Marian Robinson (L) and her niece Leslie as they tour Goree Island off the coast of Dakar in Senegal on June 27, 2013.