Table:
|  | Estimated Useful Lives (years) (1) | December 31, 2019 | December 31, 2018 |
| --- | --- | --- | --- |
| Towers | Up to 20 | $13,930.7 | $12,777.9 |
| Equipment (2) | 2 - 20 | 1,897.3 | 1,667.3 |
| Buildings and improvements | 3 - 32 | 638.9 | 628.5 |
| Land and improvements (3) | Up to 20 | 2,486.1 | 2,285.4 |
| Construction-in-progress |  | 372.6 | 358.1 |
| Total |  | 19,325.6 | 17,717.2 |
| Less accumulated depreciation |  | (7,241.2) | (6,470.1) |
| Property and equipment, net |  | $12,084.4 | $11,247.1 |
Paragraphs:
AMERICAN TOWER CORPORATION AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Tabular amounts in millions, unless otherwise disclosed)
3. PROPERTY AND EQUIPMENT
Property and equipment (including assets held under finance leases) consisted of the following:
(1) Assets on leased land are depreciated over the shorter of the estimated useful life of the asset or the term of the corresponding ground lease taking into consideration lease renewal options and residual value.
(2) Includes fiber and DAS assets.
(3) Estimated useful lives apply to improvements only.
Question:
What was the estimated useful life of Towers in years?
Answer: Up to 20