Sean Gallup / Getty Images

Messina Weiss, 12 and great grand-daughter of Holocaust survivor Gertrud Rocher, carries a flower past the memorial to the Sinti and Roma in Berlin, Germany, on Wednesday.

Germany remembered the Holocaust's forgotten victims on Wednesday by opening a memorial in the heart of Berlin to the 500,000 ethnic Sinti and Roma murdered by the Nazis.

As the mournful strains of a solo violin sounded through the trees, political leaders and frail survivors approached a dark pool close to the German parliament building.

Its still water is intended to evoke tears for the dead but also, in reflecting the beholder, inspire new generations to protect minorities from hate.

"This memorial commemorates a group of victims who, for far too long, received far too little public recognition — the many hundreds of thousands of Sinti and Roma who were persecuted by the Nazis as so-called gypsies," said German Chancellor Angela Merkel. "The destiny of every single person murdered in this genocide is one of unspeakable suffering. Every single destiny, fills us, fills me, with sadness and shame."

The memorial was designed by the Israeli artist Dani Karavan, the BBC reported, and a chronology of the Nazis' extermination campaign appears next to the memorial. A fresh flower will be placed on the triangular surface at the center of the reflecting pool every day, the BBC said.

Discrimination against Sinti and Roma increased at alarming levels once Adolf Hitler took power in 1933. They were sent to forced labor camps and, from 1934, subjected to forced sterilization as a result of the Nazis' "racial purity" laws.

Thomas Peter / Reuters

People lay flowers during the dedication of the memorial to the Sinti and Roma in Berlin, Germany, on Wednesday.

By the start of World War II, the Nazis' genocidal intent became clear as Sinti and Roma were deported to death camps, where they wore uniforms bearing a "Z" for "Zigeuner" (the German word for "gypsy").

The first time a German leader recognized Nazi persecution of the Roma on racist grounds was in 1982, more than 30 years after West Germany acknowledged the murder of 6 million Jews and began to pay compensation to Israel.

Discrimination today
German politicians and Roma leaders at the opening ceremony described the memorial as a reminder of the urgent need to protect minorities today.

Many of Europe's 12 million Roma face discrimination and social exclusion, often living in dire poverty.

"Half a million Sinti and Roma, men, women and children, were murdered during the Holocaust. Society has learned nothing, next to nothing from this, otherwise they would treat us differently," said Dutch Sinto survivor Zoni Weisz.

His voice faltered as he described how, as a seven-year-old, he watched his father, mother, sisters and brother being deported in a train to Auschwitz concentration camp.

Merkel stressed it was a German and European duty to protect Roma rights. After her speech, a heckler highlighted that Germany refuses to grant asylum to Roma from countries such as Serbia and Macedonia, where they face discrimination.

Romani Rose, leader of the Central Council of Sinti and Roma in Germany, also attended the ceremony.

"Opening the memorial sends an important message to society that anti-Roma sentiment is as unacceptable as anti-Semitism," he told AFP.

Reuters contributed to this report.

More world stories from NBC News:

• Top 10 foreign policy issues facing a new president
• Syria agrees to ceasefire during Eid holiday, says mediator
• 'The new Afghanistan'? West turns its attention to Mali
• BBC ripped for handling of sex abuse scandal tied to former host
• Castro: I'm so healthy I don't 'even remember what a headache is'
• Hate crimes increase, extreme right strengthens as Greece economy sinks
• Source: No deal yet on US-Iran nuclear talks
• Newlywed Afghan beheaded for her refusal to become prostitute

Follow World News from NBCNews.com on Twitter and Facebook