Final answer:
A caldera is the volcanic feature that evidences the scars of a volcano's last large explosive eruption, often forming a depression that can become a lake.
Step-by-step explanation:
The feature of a volcano that shows the scars of the last large explosive eruption is known as a caldera. A caldera forms when the summit of a volcano collapses following an eruption, leading to the creation of a large depression at the top of the volcano. This depression can sometimes fill with water to form a lake, as seen at Mt. Pinatubo in the Philippines.
The massive eruption of Mt. Pinatubo in 1991 was one of the largest eruptions in over a century and caused a significant impact on global climate. Other examples of volcanic features include pyroclastic flows, ash plumes, and characteristic craters which can offer a glimpse into the dynamic geology of Earth's crust.