American archaeologists have discovered two monumental royal tombs dating from about 3,500 years ago in southern Greece.
Officials say the dome roofs of both chambers near the Bronze Age palace of Pylos collapsed during antiquity and filled with so much earth and rubble grave robbers couldn't get in to plunder them.
Nevertheless, they were disturbed over several generations unlike a nearby Mycenaean grave found in 2015 that yielded a stunning hoard of gold, silver and jewellery buried with a presumed early ruler of Pylos.
Recovered goods from the two tombs include a golden seal ring and a golden amulet of an ancient Egyptian goddess, highlighting Bronze Age trade and cultural links.
Greece's culture ministry said on Tuesday the discovery was particularly important in shedding light on the early phases of the Mycenaean civilisation.
The Mycenaean era, roughly 1650-1100 BC, provided the material for many of the myths and legends of ancient Greece including that of the Trojan War.
The larger of the two tombs has a diameter of 12 meters at floor level and its stone walls have survived to 4.5 meters - less than half their original height.
The other is about two-thirds the size and its walls now stand two meters high.
Both belong to the tholos type of tomb, massive domed underground constructions reserved for Mycenaean royalty that could reach roughly 15 meters high.
They were excavated over the past two years by University of Cincinnati archaeologists, who also discovered the nearby rich burial that is known as the Griffin Warrior grave, after some of the ornaments found in it.
All three graves, together with another tholos tomb found decades ago, were built before the sprawling palace whose ruins lie close by and feature in Homer's Odyssey as the seat of King Nestor.
Australian Associated Press