The tragedy here was an unforgettable episode in human history, which is grievous and should be remembered forever, Wen told reporters at the Auschwitz-Birkenau State Museum, a memorial to those killed in World War II, which locates on the outskirts of the Krakow city.

Only by always bearing history in mind can people build a bright future, he said, adding the catastrophe at the concentration camp was one of all humanity.

The tragedy also warned people against war, terror, genocide and all crimes, and encouraged them to fight for freedom, dignity, safety and well-being, Wen said.

The nations, which waged war on others, need to reflect on their history, he stressed.

Although the disaster was over, its lessons should be learnt by mankind forever, he added.

Wen wrote on the guest book that: People can't embrace a beautiful future without understanding history.

Wen arrived in Poland on Wednesday for an official visit. Poland was the last leg of his four-nation Europe tour that also took him to Iceland, the Hannover Messe, a world leading industrial fair in Germany, and Sweden.