Around the world, time is given using different references — UTC, GMT, London time, each country's local time — and working out the difference with each one is a hassle. With madrid2036.org we use a single reference point, Madrid time: enter your time and the other person will automatically see theirs, with no calculations.
Imagine you're in Murcia and want to arrange a call with someone in New York.
Enter the time and date of the meeting/conference.
You enter your message, for example "Shall we do the call?", in the "Message" field.
You tap "Send via WhatsApp" and send it to your contact.
When they open the link from New York, they automatically see: "You're invited to meet at 19:00, Madrid time → Your time: 13:00".
Each person sees their own time in WhatsApp when they open the link, with nothing to calculate.