The observation decks on levels 124 and 125 are the reason most people come to Downtown. Tickets are timed, and the price changes sharply depending on the slot you pick.
What it costs: from AED 179 for a non-prime slot booked online. Prime-time slots around sunset cost roughly double, and buying at the ticket counter on the day is the most expensive way to do it.
Our advice: take the earliest morning slot. It is the cheapest tier, the queues are shortest, and the haze that builds through the day has not arrived yet. Allow about 90 minutes including security.
Getting there: Burj Khalifa/Dubai Mall Metro station, then roughly a 15-minute covered walk through the mall.