Tambora's 1815 eruption was the largest in recorded human history and the largest of the Holocene (10,000 years ago to present). The magma chamber under Tambora had been drained by pre-1815 eruptions and underwent several centuries of dormancy as it refilled. Volcanic activity reached a peak that year, culminating in the explosive eruption. The explosion was heard on Sumatra island, more than away. Heavy volcanic ash rains were observed as far away as Borneo, Sulawesi, Java and Maluku islands, and the maximum elevation of Tambora was reduced from about to . Although estimates vary, the death toll was at least 71,000 people. The eruption contributed to global climate anomalies in the following years, while 1816 became known as the year without a summer due to the impact on North American and European weather. In the Northern Hemisphere, crops failed and livestock died, resulting in the worst famine of the century.