Approximately 141 million Valentine's Day cards are exchanged worldwide every year.
104
Historically, sweat has been an active ingredient in perfume and love potions.
309
When dragonflies mate, their tails form a love heart.
22
The single biggest predictor of love is proximity.
30
Couples' personalities converge over time to make partners more and more similar.
235
When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
25
Falling in love raises levels of nerve growth in a person's brain for about a year and can improve their memory.
39