Conversation so far:
when did they start building the london underground
The history of the London Underground began in the 19th century with the construction of the Metropolitan Railway which opened in 1863.
did any disasters happen in 1863
The blizzard and flood of 1863 was a series of consecutive natural disasters in Central Otago in New Zealand's South Island.
how many people died in The blizzard and flood of 1863
At least 40 died during the July rains and more than 11 in the August snows during the Blizzard and flood of 1863.

Question: were the deaths memorialized
Self-contained rewrite: were the deaths in the blizzard and flood of 1863 memorialized