The interior serves not only as a chapel, but also as a major work of modern art: on its walls are fourteen paintings by Mark Rothko in varying hues of black.

[2] Susan J. Barnes states "The Rothko Chapel ... became the world's first broadly ecumenical center, a holy place open to all religions and belonging to none.

As Rothko was given creative license on the design of the structure, he clashed with the project's original architect, Philip Johnson over the plans for the chapel.

From 1973 onward, the Rothko Chapel doubled as a center for colloquiums aimed at fostering mutual understanding on issues affecting justice and freedom throughout the world.

The first colloquium drew scholars from Lebanon, Iran, India, Pakistan, Nigeria, Japan, Italy, the United States and Canada.

In 1991 the Rothko Chapel marked its 20th anniversary with a joint award with the Carter-Menil Human Rights Foundation, founded in 1986 with former President Jimmy Carter.

As renovated in 2020 by Architecture Research Office and George Sexton Associates, the louvered skylight diffuser consists of 280 reflective aluminum blades that are individually angled and spaced to ensure an even distribution of light onto the paintings along the perimeter walls.

The sculpture sits in a reflecting pool designed by Philip Johnson and it is dedicated to the memory of Martin Luther King Jr., who was assassinated in 1968.

The sculpture originally stood in Washington, D.C., and was offered in 1969 by the de Menils as a memorial to King to stand in front of Houston City Hall.

[22] The Rothko Chapel also hosts the biannual Óscar Romero Award to recognize "courageous, grassroots, human rights advocacy.

"[23] Past awardees include Bishop Proaño, Cardinal Arns, the Oslobodjenje, Sr. Dianna Ortiz, Salima Ghezali, and Berta Cáceres.